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Full text of "Projected effects of increased diversion of Lake Michigan water on the environment of the Illinois River Valley"

HAVANA 
COPY 



/^OUATIC 
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PROJIiCTED EFFHCTS OF IXCRl-ASi-D HIVHRSION 
OF LAKH M1CI1I(;A.\ IVATliR 



OX THE ENVIROXMEXT OF Til 



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Frank C. Be 1.1 r 

H. Kathleen Archer, Wildlife Assi 



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Fred Paveqli 



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Donald W . SteiTeck, Wildlife Assistant 
Aqua t i L Sect i on: 

Kenneth S. Liibinski, Aquatic Biolopjst 
Richard E. Sparks, Aquatic Rioloeist 
IVarren U. Brinham, Aquatic Biologist 
Larry Coutant, Aquatic Assistant' 



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uatic Assistai 



Dee "^'cCormi ck , Aquatic Assistant 
Illinois Natural History Survev 



lavana and Urbana 



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Prepared for the Chicai 



o District, U.S. Ar 



Corps oi' Engineers 




Wilson 447-13 
\m^ Jones 



REDICOVERS 



PROJECTED EFFECTS OF INCREASED DIVERSION 
OF LAKE MICHIGAN WATER 
ON THE ENVIRONMENT OF THE ILLINOIS PI\^R VALLEY 

Wildlife Section: 

Stephen P. Havera, Wildlife Specialist 
Frank C. Bellrose, Wildlife Specialist 
H. Kathleen Archer, Wildlife Assistant 
Fred Paveglio, Jr., Wildlife Assistant 
Donald W. Steffeck, Wildlife Assistant 

Aquatic Section: 

Kenneth S. Lubinski, Aquatic Biologist 
Richard E. Sparks, Aquatic Biologist 
Warren U. Brigham, Aquatic Biologist 
Larry Coutant, Aquatic Assistant 
Stephen Waite, Aquatic Assistant 
Dee McCormick, Aquatic Assistant 

Illinois Natural History Survey, Havana and Urbana 
July 1980 
Prepared for the Chicago District, U.S. Army Corps of Engineers 



Digitized by tine Internet Arciiive 

in 2010 witii funding from 

CARLI: Consortium of Academic and Researcii Libraries in Illinois 



http://www.archive.org/details/projectedeffectsOOunit 



^. >" XL... 



TABLE OF CONTENTS 

Page 

LIST OF TABLES viii 

LIST OF FIGURES xxii 

SECTION I. INTRODUCTION 

CHAPTER 1: PURPOSE AND SCOPE 1-1 

DESCRIPTION OF THE ILLINOIS WATERWAY 1-1 

THE PROJECT 1-5 

CHAPTER 2: PHYSICAL AND WATER QUALITY CHANGES 

ASSOCIATED WITH INCREASED DIVERSION . . . 2- 1 

INTRODUCTION 2-1 

PHYSICAL CHANGES 2-1 

Absolute Water Levels 2-1 

Water Level Stability 2-3 

Velocity 2-5 

WATER QUALITY CHANGES 2-6 

Dissolved Oxygen 2-6 

Suspended Sediment and Turbidity 2-8 

Toxic Materials 2-11 

Temperature 2-11 

General Mineral Content 2-12 

SECTION II. TERRESTRIAL ENVIRONMENT 

CHAPTER 3: INTRODUCTION TO WILDLIFE STUDIES 3-1 

CHAPTER 4: SURFACE AREA AND VOLUME OF BOTTOMLAND 

LAKES IN THE ILLINOIS RIVER VALLEY . . . .4-1 

METHODS 4-1 

Surface Area 4-1 

Volume 4-2 

Average Depth 4-20 

Mud Flat Area and Percent Occurrence of 

Water Levels 4-20 

RESULTS 4-26 

EFFECTS OF DIVERSION 4-27 

Surface Area . ; 4-27 

Mud Flats . . ■.■ 4-28 

Volume . . . . 4-29 

Comparisons 4-29 

Average Depth 4-29 



Page 

CHAPTER 5: VEGETATION 5-1 

BOTTOMLAND FOREST 5-1 

Black Willow-Cottonwood Community 5-1, 

Mixed Softwoods 5-2 

Mixed Community 5-3 

Uplands or Oak-Hickory Community 5-4 

Islands , 5-5 

Bottomland Forest-Water Relationships . . . 5-6 

Season of Flooding 5-7 

Depth of Flooding 5-8 

Duration of Flooding 5-8 

Flooding Frequency ... 5-10 

Velocity . . . . ' 5-10 

Elevation 5-10 

Tree Size and Condition 5-11 

Seedlings 5-11 

Sediment Effects 5-12 

Soil Texture 5-12 

Flooding and Water Tolerances of Bottomland 

Tree Species 5-13 

Flooding Tolerances of Tree Species .... 5-13 

Field Inventory of Bottomland Forest .... 5-17 

Effects of Diversion 5-38 

SHRUBS 5-4 2 

1978 Field Inventory 5-44 

Effects of Diversion 5-44 

HERBACEOUS VEGETATION -- FORBS AND GRASSES ... 5-46 

Effects of Diversion 5-46 

WETLAND VEGETATION ..... 5-47 

EMERGENT, SUBMERGENT, AND FLOATING AQUATICS . . .5-48 

Emergent Vegetation 5-48 

Submergent and Floating Aquatic Plants . . . 5-52 
The Effects of Increased Diversion on 
Emergent, Submergent, and Floating Aquatic 

Plants S-59 

MOIST-SOIL PLANTS 5-66 

Spring Lake 5-66 

Rice Lake 5-68 

Teal Grass ( Eragrostis ) 5-70 

Rice Cutgrass (Leersia oryzoides ) 5-75 

Millets ( Echinochloa sp.) . . T 5-76 

Nutgrasses ( Cyperus sp.) 5-79 

Smartweeds ( Polygonum sp.) 5-83 

Pigweed ( Acnida , sp.) 5-87 

Beggar- ticks ( Bidens sp.) 5-88 

The Effects of Increased Diversion on Moist- 
Soil Plants 5-89 



ii 



Page 

CHAPTER 6: WATERFOWL HUNTING AREAS 6-1 u 

EFFECTS OF INCREASED DIVERSION 6-6 

Peoria Pool 6-11 

La Grange Pool 6-12 

Alton Pool 6-13 

All Pools 6- 17> 

CHAPTER 7: WATERFOWL POPULATIONS 7-1 

EFFECTS OF FOOD RESOURCES ON WATERFOWL POPULATIONS 7-10 
EFFECTS OF PROPOSED DIVERSION ON WATERFOWL 

POPULATIONS 7-14 

WINTER AND SPRING WATER LEVELS 7-15 

CHAPTER 8: WATERFOWL HARVEST 8-1 

EFFECTS OF DIVERSION 8-7 

CHAPTER 9: SHOREBIRDS, GULLS, AND TERNS 9-1 

WADING SHOREBIRDS 9-1 

GULLS AND TERNS 9-2 

19 78 FIELD INVENTORY 9-3 

Wading Shorebirds 9-5 

Gulls and Terns 9-24 

EFFECTS OF INCREASED DIVERSION 9-25 

CHAPTER 10: HERONS AND THEIR ALLIES 10-1 

1978 FIELD INVENTORIES 10-4 

EFFECTS OF INCREASED DIVERSION 10-6 

CHAPTER 11: BALD EAGLES, DOUBLE-CRESTED CORMOR.ANTS , 

AND MISSISSIPPI KITES 11-1 

BALD EAGLE 1 1 - 1 

1978 Field Inventory 11-2 

Effects of Increased Diversion 11-4 

DOUBLE-CRESTED CORMORANTS 11-5 

MISSISSIPPI KITE n-8 

CHAPTER 12: OTHER AVIFAUNA 12-1 

ORDER GAVIIFORMES 12-1 

ORDER PODICIPEDIFORMES 12-1 

ORDER FALCONIFORMES 12-1 

ORDER GALLIFORMES, FAMILY PHASIANIDAE 12-2 

ORDER GRUIFORMES, FAMILY RALLIDAE 12-2 

ORDERS COLUMB I FORMES AND CUCULIFORMES 12-2 

ORDER STRIGIFORMES 12-3 

ORDER CAPRIMULGIFORMES 12-3 

ORDER APODIFORMES 12-4 

ORDER COR.ACIIFORMES, FAMILY ALCEDINIDAE 12-4 



V 



Page 

ORDER PICIFORMES 12-4 

ORDER PASSERIFOR^fES 12-5 

FIELD INVENTORIES 12-6 

EFFECTS OF INCREASED DIVERSION 12-18 '"> 

CHAPTER 13: MAM^IALS 13-1 

NATURAL HISTORY 13-1 

Order Marsupialia 13-1 

Order Insectivora 13-1 

Order Chiroptera 13-2 

Order Lagomorpha 13-2 

Order Rodentia 13-2 

Order Carnivora 13-4 

Order Artiodactyla 13-5 

MAMMALS OF RECREATIONAL AND ECONOMIC IMPORTANCE . 13-6 

Small Game Mammals 13-6 

White-tailed Deer 13-10 

Furbearers 13-10 

' EFFECTS OF AN INCREASED DIVERSION 13-14 ^^ 

CHAPTER 14: STATE AND FEDERAL AREAS, NATURE PRESERVES, 

AND NATURAL AREAS 14-1 

EFFECTS OF DIVERSION 14-6 



SECTION III. AQUATIC STUDIES 

CHAPTER 15: INTRODUCTION TO THE AQUATIC STUDIES . . . 15-1 

OBJECTIVES 15-1 

THE AQUATIC HABITATS OF THE ILLINOIS WATERWAY . . 15-1 

Aquatic Habitat Descriptions 15-1 

AQUATIC HABITAT DISTRIBUTION 15-3 

AQUATIC STUDIES 15- 5 

CHAPTER 16: ALGAE (PERIPHYTON AND PHYTOPLANKTON) . . 16-1 

INTRODUCTION 16-1 

PAST MEASUREMENTS OF ALGAL POPULATIONS IN THE 

ILLINOIS RIVER 16-1 

Problems Connected with Comparing Results 

of Past Studies 16-1 

Pre-1900 . , 16-2 

Post- 1900 ! ' ' ' 16-7 

CURRENT STATUS OF ALGAE IN THE WATERWAY .. * * * 16-12 

RESULTS -." * 16-16 

PROBABLE EFFECTS OF INCREASED DIVERSION On'tHe' 

ALGAE OF THE ILLINOIS RIVER 16-27 

PROBABLE ADVERSE EFFECTS OF INCREASED LAKE* 

MICHIGAN DIVERSION ON THE ALGAE IN THE WATERWAY 

WHICH CANNOT BE AVOIDED 16-30 



IV 



CHAPTER 17: ZOOPLANKTON ^^ ^ 

INTRODUCTION . ' ]^'] 

HISTORICAL PERSPECTIVE 7- 

Pre-190n '^'' 

Post-1900 ]^-; 

STATUS OF EXISTING ZOOPLANKTON POPULATIONS . . . 17-7 

Description of Sampling Areas ^^'ii 

Methodology i- n 

Results li zl 

Summary of Results i/-^^ 

PREDICTED EFFECTS OF INCREASED DIVERSION ON 

ILLINOIS WATERWAY ZOOPLANKTON Vi' -I 

Velocity ]l' il 

Turbidity i-f 

Temperature iv'^v 

Toxic Materials i7 70 

Elimination of Backwaters ]l' ^l 

MITIGATIVE ACTIONS 1/-:>« 

CHAPTER 18: mCROINVERTEBRATES IS-I 

HISTORICAL CHANGES ]^-1^ 

PRESENT CONDITIONS ^" - 

Benthic Macroinvertebrates o'ia 

Unionid Mussels 10" 17 

Drift Organisms ■ *■ 10 ii 

Contrast Between Benthic and Drift Communi t les 1«-Zb 
POSSIBLE EFFECTS OF INCREASED DIVERSION ON 

MACROINA^RTEBRATES ]l -n 

SUM^LARY ib-^U 

CHAPTER 19: FISH , "■ ^ " "■ 

INTRODUCTION J^"^ 

Obiectives '■'' 

FISH POPULATIONS OF THE ILLINOIS WATERWAY . . . . 9- 

Data Bases and Project Areas J9-1 

Sampling Stations m in 

Methods ]o ^- 

Results_ \l-_l' 

Discussion 10 7Q 

Illinois River Summary 1 y - / 1> 

THE IMPACTS OF INCREASED DIVERSION ON ILLINOIS 

WATERWAY FISH POPULATIONS 19-79 

Impacts Related -to Water Quality Changes . . 19-/9 

Impacts Related to Aquatic Habitat Quantity 

and Quality ^-«9 

SUMMARY OF IMPACTS '-^^ 



SECTION IV. THREATENED AND ENDANGERED VERTEBRATES 
OF THE ILLINOIS WATERWAY 

Page 

CHAPTER 20: THREATENED AND ENDANGERED VERTEBRATES 

OF THE ILLINOIS WATERWAY 20-1 

INTRODUCTION 20-1 

FISHES 20-2 

Lake Sturgeon 20-2 

Alligator Gar 20-2 

Cisco 20-3 

Blacknose Shiner 20-3 

Bantam Sunfish . . . , 20-4 

AMPHIBIANS 20-5 

Illinois Chorus Frog , 20-5 

REPTILES 20-6 

Spotted Turtle 20-6 

Slider 20-6 

Illinois Mud Turtle 20-7 

Western Hognose Snake . , 20-8 

Great Plains Rat Snake 20-9 

BIRDS 20-10 

MA^tT•AALS 20-15 

ADDITIONAL INFORMATION ON ENDANGERED SPECIES . . 20-15 

SUMMARY OF EFFECTS OF INCREASED DIVERSION . , . . 20-16 



SECTION V. SUMMARY OF EFFECTS Or INCREASED DH^RSION 

CHAPTER 21: SUMMARY OF EFFECTS OF INCREASED DIVERSION 21-1 

CHAPTER 4. SURFACE AREA AND VOLUME OF BOTTOMLAND 

LAKES IN THE ILLINOIS RIVER VALLEY 21-1 

CHAPTER 5. VEGETATION 21-2 

Bottomland Forest 21-2 

Shrubs 21-3 

Herbaceous Vegetation -- Forbs and Grasses . 21-3 
Wetland Vegetation -- Emergent, Submergent, 

and Floating Aquatic 21-3 

Wetland Vegetation -- Moist-Soil Plants . . 21-4 

CHAPTER 6. WATERFOWL HUNTING AREAS 21-5 

CHAPTER 7. WATERFOWL POPULATIONS 21-6 

CHAPTER 8. WATERFOWL HARVEST 21-7 

CHAPTER 9. SHOREBIRDS, GULLS, AND TERNS .... 21-7 

CHAPTER 10. HERONS AND THEIR ALLIES 21-7 

CHAPTER 11. BALD EAGLES, DOUBLE-CRESTED CORMOR- 
ANTS, AND MISSISSIPPI KITES 21-8 

Bald Eagles 21-8 

Double-crested' Cormorants , 21-8 jj 

Mississippi Kite 21-9 

CHAPTER 12. OTHER AVIFAUNA 21-9 

CHAPTER 13. MAMMALS 21-9 

CHAPTER 14. STATE AND FEDERAL AREAS, NATURE 

PRESERVES, AND NATURAL AREAS 21 -H: 



Page 

CHAPTER 16. ALGAE (PERIPIIYTON A\D PHYTOPLANKTON) 21-10 

CHAPTER 17. ZOOPLANKTON 21-11 

CHAPTER 18. M.A,CRO INVERTEBRATES 21-12 

CHAPTER 19. FISH 21-12 

SECTION VI. REFERENCES 

CHAPTER 22: LITER./\TURE CITED 22-1 



APPENDIX A: 
APPENDIX B: 

APPENDIX C: 

APPENDIX D; 

APPENDIX E 
APPENDIX F 
APPENDIX G 
APPENDIX H 



SECTION VII. APPENDICES 

PHYSICAL AND WATER QUALITY EFFECTS -. 

METRIC EOUIVALENTS OF TABLES PRESENTED 
IN CHAPTER 4: INCLUDING SURFACE AREA, 
VOLUME AND AREA OF ^njD FLATS OF VARIOUS 
BOTTOMLAND LAKES IN THE ILLINOIS WATERWAY 

ANNOTATED SPECIES LISTS OF THE FLORA AND 
FAUNA IN THE PROJECT AREA 

LIST OF PRIVATE LICENSED WATERFOWL 
HUNTING CLUBS 

ALGAE (PERIPHYTON AND PHYTOPLANKTON) i ■; 

ZOOPLANKTON 

FISH 

LIST OF PERSONNEL CONTACTED FOR INFORMATION 
UTILIZED IN THIS REPORT 



Vll 



LIST OF TABLES 

Page 

Table 2-1. Physical and Water Quality Changes Related 
to Diversion that could influence the 
Aquatic and Terrestrial Life of the 
Illinois Waterway 2-2 

Table 2-2. Mean Concentrations of Certain Water 

Quality Constituents (mg/l) 2-7 

Table 3-1. Predicted Average Gauge Readings in msl 
(ft) from the Computer Models for Henry 
(Peoria Pool) with No Additional Diver- 
sion, 6,600-cfs Diversion, and 10,000- 
cfs Diversion 3-4 

Table 3-2. Predicted Average Gauge Readings in msl 
(ft) from the Computer Models for Havana 
(La Grange Pool) with No Additional Diver- 
sion, 6,600-cfs Diversion, and 10,000- 
cfs Diversion 3-5 

Table 4-1. Surface Area of Lakes between Chicago 

and Starved Rock Lock and Dam (Upper Pools) 4-3 

Table 4-2. Surface Area of the Lakes in the Peoria 

Pool 4-4 

Table 4-3. Surface Area of the Lakes in the La Grange 

Pool 4-5 

Table 4-4. Surface Area of the Lakes in the Alton 

Pool from La Grange to Grafton, Illinois . 4-7 

Table 4-5. Total Surface Area of the Lakes in the 

Entire Illinois River Valley from Chicago 

to Grafton 4-8 

Table 4-6. Surface Area (Acres) and Volume (Acre-Feet) 
of Selected Bottomland Lakes (above Peoria 
Lake) in the Peoria Pool based on 0.5-ft 
Contour Intervals below the 1978 Tree Line 4-9 

Table 4-7. Surface Area (Acres) and Volume (Acre-Feet) 
of Upper Peoria Lake (Peoria Pool) based 
on 0.5- and I.O^ft Contour Intervals below 
Normal Pool Elevation 4-12 

Table 4-8. Surface Area (Acres) and Volume (Acre-Feet) 
of Selected Bottomland Lakes in the La 
Grange Pool based on 0.5-ft Contour 
Intervals below the 1978 Tree Line .... 4-13 

Table 4-9. Surface Area (Acres) and Volume (Acre-Feet) 
of Selected Bottomland Lakes in the Alton 
Pool from La Grange to Grafton, Illinois 
based on 0.5-ft Contour Intervals below 
the 1978 Tree Line 4-16 



Vlll 



Page 

Table 4-10. Surface Area (Acres) and Volume (Acre-Feet] 
of the Bottomland Lakes in the Entire 
Illinois River Valley, Utica to Grafton, 
Illinois, based on 0.5-ft Contour Intervals 
below the 1978 Tree Line 4-17 

Table 4-11. The Number of Acres of Mud Flats Exposed in 
Certain Lakes of the Peoria Pool in Relation 
to Mean Sea Level River Stages at Henry for 
the Entire Growing Season of 10 July- 1 
October, 1939-1978 '. . . . 4-22 

Table 4-12. The Number of Acres of Mud Flats exposed 
in Certain Lakes of the La Grange Pool in 
relation to Mean Sea Level River Stages at 
Havana for the Entire Growing Season of 10 
July-1 October, 1939-1978 4-25 

Table 5-1. Classification of Water Level Tolerances 
of Tree Species that may occur in the 
ProjectArea 5-14 

Table 5-2, Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland 
Tree Species sampled near Hennepin (Peoria 
Pool) ' ' 5-20 

Table 5-3. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Big Spring (Peoria Pool) 5-21 

Table 5-4. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Marshall County Conser- 
vation Area (Peoria Pool) 5-22 

Table 5-5. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Spring Branch Conserva- 
tion Area (Peoria Pool) 5-23 

Table 5-6. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Duck Island (La Grange 
Pool) 5-24 

Table 5-7. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Clear Lake (La Grange 
Pool) 5-2 5 

Table 5-8. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Grand Island (La Grange 
Pool) ...-.■ 5-26 

Table 5-9. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Sanganois Conservation 
Area (La Grange Pool) 5-27 



IX 



Page 

Table 5-10. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Sanganois Conservation 
Area (La Grange Pool) 5-28 

Table 5-11. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled in Lynchburg Township, 
Mason County (La Crange Pool) 5-29 

Table 5-12. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Mark Twain National 
Wildlife Refuge, Meredosia Division (Alton 
Pool) 5-30 

Table 5-13. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Mark Twain National 
Wildlife Refuge, Meredosia Division (Alton 
Pool) 5-31 

Table 5-14. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Big Blue Island (Alton 
Pool) 5-32 

Table 5-15. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Godars Swamp State Con- 
servation Area (Alton Pool) 5-33 

Table 5-16. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at The Glades State Con- 
servation Area (Alton Pool) 5-34 

Table 5-17. Density, Average DBH, Basal Area, and Saw- 
timber Dollar Value of the Bottomland Tree 
Species sampled at Island 525, Calhoun 
Point State Conservation Area (Alton Pool) 5-35 

Table 5-18. Average Gauge Readings in msl (ft) for 

Henry (Peoria Pool) and Havana (La Grange 
Pool) calculated from the U.S. Weather Ser- 
vice River Stage Records with the Addition 
of the Increase in Water Levels as predicted 
by the Computer Models for the 6,600- and 
10,000-cfs Diversion . . . , 5-40 

Table 5-19. Percent Frequency of Occurrence of Woody 
Understory Plants _<10 cm (4 in) DBH in 
Bottomland Forest "on Grand Island (La 
Grange Pool) 5-45 

Table 5-20. Secchi Disk Readings taken at Various 

Locations in the Illinois River Channel, 
September-October, 1978 5-56 



Tabic 5-21. The Approximate Number of Hectares (Acres) 
of Mud Flats at 0.5-Foot Intervals in the 
Peoria and La Grange Pools for the Growing 
Period of 10 July to 1 October and the 
Percent of Years from 1939 to 1978 that 
Each Level was exposed 5-62 

Table 5-22. Drawdown Date, Length of Exposure, and Soil 
>'oisture of the Vegetative Sampling Tran- 
sects at Two Rice Lake Study Areas .... 5-69 

Table 5-23. Percent Occurrence and Average Percent 
Coverage of Moist-Soil Plants at Rice 
Lake, September 1978 5-71 

Table 5-24. Percent Occurrence and Average Percent 
Coverage of Moist-Soil Plants at Spring 
Lake, September 1978 5-72 

Table 5-25, Average Height, Percent Occurrence, and 
Average Percent Coverage of the Major 
Moist-Soil Plant Species by Transect at 
the Rice Lake Study Areas, September 1978 5-73 

Table 5-26. Average Height, Percent Occurrence, and 
Average Percent Coverage of the Major 
Moist-Soil Plant Species by Transect at 
Spring Lake, September 1978 5-74 

Table 5-27. Average Gauge Readings in ms 1 (ft) for 

Henry (Peoria Pool) and Havana (La Grange 
Pool) calculated from the U.S. Weather 
Service River Stage Records with the Addi- 
tion of the Increase in Water Levels as 
Predicted by the Computer Models for the 
6,600- and 10,000-cfs Diversion 5-90 

Table 6-1. Total Hectares (Acres) and Number of Duck 
Clubs Bordering the Illinois River bv 
Counties, 1977 ' . . . 6-2 

Table 6-2. Summary of the Questionnaire Responses 

from Private Duck Clubs along the Illinois 
River, 1978 6-4 

Table 6-3. The Number of Hectares (Acres) of State 

and Federal Lands with Waterfowl Management 
Units and the Size of Their Respective 
Waterfowl Impoundments 6-5 

Table 6-4. The Number of Hectares (Acres) of Private 
Duck Clubs with Water Control that would 
be Inundated at the Various Respective 
River Levels in the Peoria Pool 6-7 

Table 6-5. The Number of Hectares (Acres) of Private 
Duck Clubs with Water Control that would 
be Inundated at the Various Respective 
River Levels in the La Grange Pool .... 6-8 



XI 



Page 

Table 6-6. The Number of Hectares (Acres) under Water 
Control by the U.S. Fish and V.'ildlife Ser- 
vice and the Illinois Department of Conser- 
vation that Would Be Inundated at the 
Various Respective Water Levels in La 
Grange Pool , 6-9 - 

Table 6-7. The Number of Hectares CAcres) of State 
and Federal Lands with Water Control in 
the Alton Pool and the Heights of Their 
Respective Levees , . 6-10 

Table 7-1. Fall Waterfowl Use-Days and Use-Days per 

Hectare of Water Surface in the Navigation 
Pools of the Illinois River, 1976-1978 . . 7-2 

Table 7-2. Spring Waterfowl Use-Days and Use-Days per 
Hectare of Water Surface in the Navigation 
Pools of the Illinois River, 1977-1979 . . 7-3 

Table 7-3. Percent Species Composition of the Fall 
Waterfowl Populations in the Illinois 
River Valley, 1976-1978 7-4 

Table 7-4. Percent Species Composition of the Spring 
Waterfowl Populations in the Illinois 
River Valley, 1977-1979 7-5 

Table 7-5. V/inter Waterfowl Use-Days in the Naviga- 
tion Pools of the Illinois River, 3 
January, 1977-1979 7-7 

Table 7-6. Multiple Regression Coefficients of Index 
of Duration of Stay of Waterfowl Species 
(Y) in Relation to Summer and Fall Water 
Levels (X), Peoria and La Grange Pools, 
1949-1976 7-12 

Table 7-7. The Average Height of Fall Water Levels 

Each Year CX) in Relation to Fall Abundance 
of Dabbling Ducks (Y) in La Grange Pool, 
1949-1976 7-13 

Table 8-1. Average Annual Duck Harvest in relation to 
the Water Area of Bottomland Lakes by 
Counties and Navigation Pools in the Illi- 
nois River Valley, 1966-1975 8-2 

Table 8-2. The Number, Size, Hunting Activity, and 

Duck Harvest of Private Waterfowl Hunting 
Clubs and State Public Shooting Grounds by 
Navigation Pools in the Illinois River 
Valley 8-3 

Table 8-3. Average Annual Harvest of Each Duck Species 
in the Illinois River Valley According to 
U.S. Fish 5 Wildlife Service Data compiled 
by Counties, 1966-1975, and Illinois Depart- 
ment of Conservation Records for Private 
Duck Clubs, 1976-1977 8-5 



Xll 



Page 

Table 9-1. Aerial Censuses of Total Shorebird Numbers 
in the Lower Illinois Valley (La Grange 
Pool), August-September 1978 9-5 

Table 9-2. Numbers of Shorebirds, Gulls, and Terns 
from Ground Censuses of Lake Chautauqua, 
August-September, 1978 9-6 

Table 9-3. Number of Shorebird, Gull, and Tern Use- 
Davs at Goose and Weis Lakes (Peoria 
Pool) , 1973-1978 9-9 

Table 9-4. Number of Shorebird, Gull', and Tern Use- 
Davs at Chautauqua Lake (La Grange Pool), 
1973-1978 9-10 

Table 9-5. Number of Shorebird, Gull, and Tern Use- 
Days at Meredosia Lake (Alton Pool), 1973- 
1978 9-13 

Table 9-6. Number of Wading Shorebird Use-Davs at 

Mark Twain NWR , 197 3-1978 9-15 

Table 9-7. Number of Gull and Tern Use-Days at Mark 

Twain NWR, 19 73-19 78 9-16 

Table 9-8. Predicted Number of Individuals of the 
Shorebird Species Censused Aerially, 21 
August 1978 9-18 

Table 9-9. Predicted Number of Individuals of the 
Shorebird Species Censused Aerially, 28 
August 1978 9-19 

Table 9-10. Predicted Number of Individuals of the 
Shorebird Species Censused Aerially, 5 
September 1978 9-20 

Table 9-11. Predicted Number of Individuals of the 
Shorebird Species Censused Aerially, 13 
September 1978 9-21 

Table 9-12. Average Water Levels in Meters (Feet) at 

Havana, 1973-1978 9-23 

Table 10-1. Great Blue Heron, Great Egret, and Black- 
Crowned Night Heron Colony Locations and 
Censuses, 1973-1978 . . ' 10-2 

Table 11-1. Average Bald Eagle Sightings Per Aerial 
Census by Month for the Winters of 1976, 
1977, and 1978 11-3 

Table 11-2. Spring and Fall Aerial Censuses of Double- 
Crested Cormorants in the Illinois River 
Valley, 1974-1979 11-6 

Table 12-1. Five-year Avefage of Birds Sighted per 
Party-Hour in December for Two Areas in 
the Upper Pools, 1973-1977 12-8 



Page 

Table 12-2. Five-year Average of Birds Sighted per 
Party-Hour in December for Two Areas in 

Peoria Pool, 1973-1977 12-10 

Table 12-3. Five-year Average of Birds Sighted per 
Party-Hour in December for Two Areas in 

La Grange Pool, 1973-1977 12-12 

Table 12-4. Five-year Average of Birds Sighted per 
Party-Hour in December for Two Areas in 

Alton Pool, 1973-1977 12-14 

Table 12-5. Census of Breeding Birds per 40.5 ha (100 
a) of Bottomland Forest -- Grand Island 
(La Grange Pool), 28 June 1978 12-17 

Table 13-1. Annual Cottontail Values of the Mean 
Number and Percentage Harvested and 
Hunter-trips Expended and the Mean Kill 
per Hunter-trip in the Project Area 
Counties, 1956-1969 13-7 

Table 13-2. Annual Gray and Fox Squirrel Value of the 
Mean Number and Percentage Harvested and 
Hunter-trips Expended and the Mean Kill 
per Hunter-trip in the Project Area 
Counties, 1956-1969 13-9 

Table 13-3. Deer Harvest and Hunter Success in the 

Project Area Counties, 1977 13-11 

Table 13-4. Resident Trapping License Sales for the 

Project Area Counties, 1974 and 1975 . . 13-13 

Table 13-5. Estimated Average Prices Paid for Fur- 
bearer Pelts in Illinois, 1976-1978 . . . 13-15 

Table 14-1. State Parks, State Conservation Areas, 

and Federal Wildlife Areas in the Project 

Area 14-2 

Table 14-2. Nature Preserves in the Project Area . . 14-4 
Table 14-3. Natural Areas in the Project Area .... 14-7 

Table 15-1. Surface Areas in Hectares (Acres in 

Parentheses) of Aquatic Habitats in 6 

Pools of the Illinois Waterway 15-4 

Table 16-1. Densities of Phy toplankton in the Illinois 
River at Selected Locations along the 
Illinois River System ,..,,.,,., 16-3 

Table 16-2. Densities of Phy toplankton Major Divisions 
and Total Phytoplankton Collected at 13 
Sampling Stations during July, August, 
and September 1978 in the Illinois 
Waterway , . 16-17 

Table 16-3. Densities of Periphyton Major Divisions 
and Total Periphyton Collected at 13 
Sampling Stations during August and Sep- 
tember 1978 in the Illinois Waterway , . 16-19 

xiv 



Pace 



Table 16-4. Total Number of Taxa Identified from 

Phy toplankton and Periphyton Collections 

>tade at 13 Sampling Stations in the 

Illinois U'atenvav during July, August 

and September 1978 . , . . ' 16-21 

Table 16-5. Diversity Indices of the Phy toplankton 
and Periphyton Collected at 15 Stations 
in the Illinois Waterway during July, 
August, and September 1978 16-22 

Table 16-6. Secchi Disc Transparencies at 13 Stations 
Sampled for Ph ytoplankton and Periphyton 
in the Illinois Waterway during July, 
August, and September 1978 16-26 

Table 17-1. Comparison of River Conditions and Types 
of Zooplankton Collected at Selected 
Reaches along the Illinois River by Forbes 
and Richardson (1913) and Purdy (1930) . 17-4 

Table 17-2. Limnological Data and Descriptions of 
Zooplankton Sampling Stations in the 
Illinois Waterway and Pool 26 of the 
Mississippi River, July, August, and 
September 1978 . . . ' 17-8 

Table 17-3. Comparison of Total Numbers of Zooplankton 
Taxa Collected in 1894-1899, 1974, "and 
1978 in the Illinois River 17-15 

Table 17-4. A Historical Inventory of Rotifera, 

Cladocera, and Copepoda Collected in the 
Illinois Waterway 17-16 

Table 17-5. Species Diversity Values of Zooplankton 
in the Illinois River and Pool 26 of the 
Mississippi River, July, August, and 
September 1978 17-30 

Table 17-6. Mean Biomass (mg per m') of 3 Replicate 
Samples of Total Zooplankton Plus Net 
Phvtoplankton in the Illinois Watenvay 
and Pool 26 of the i^'ississippi River, 
July, August, and September 1978 .... 17-32 

Table 18-1. Numbers and Kinds of Macroinvertebrates 
per Square Meter in the Illinois River 
in the Fall of 1975 . 18-6 

Table 18-2. Kilograms of >'acroinvertebrates per 
Hectare in the Illinois River in the 
Fall of 1975' 18-8 

Table 18-3. Benthic ^'acroi nvertebrate Abundance at 
Stations Shown in Figure 18-2 on June 
17 (Chicago River) and Julv 15, 1975 
(Calumet River) ' 18-10 



Page 

Table 18-4. Benthic Macroinvertebrate Abundance at 

Stations Shown in Figure 18-2 on Septem- 
ber 17 (Chicago River) and October 21, 
1975 (Calumet River) 18-11 

Table 18-5. Benthic Macroinvertebrate Abundance 
at Stations Shown in Figure 18-2 on 
December 9, 1975 (Chicago River) .... 18-12 

Table 18-6. Mean Density of Benthic Macroinvertebrates 
of the North Shore Channel Chicago River 
and Lower Portion of the North Branch of 
the Chicago River in 1975 -- Average of 
May, August, October Sampling Dates . . . 18-13 

Table 18-7. Comparison of Biological Conditions in 
Tributaries to the Illinois River as 
Determined by Hand-picking of Inverte- 
brates from Bottom Material in 1967, 1973, 
1976, and 1978 18-22 

Table 18-8. Comparison of Biological Conditions in 

the Illinois River as Determined by Inver- 
tebrates on Plate Samplers in 1967, 1978, 
and 1973 18-23 

Table 19-1. Description of the Ten Watersheds in the 

Upper Illinois Waterway 19-4 

Table 19-2. List of Fishes Collected from the Subdi- 
visions of the Illinois Waterway and the 
Relative Abundance of Each 19-15 

Table 19-3. Relative Abundance of Fishes in Aquatic 

Habitats of the Illinois Waterway .... 19-28 

Table 19-4. Illinois River Minnow Seine Summary (1978) 19-41 

Table 19-5. Illinois River Minnow Seine Summary (1979) 19-42 

Table 19-6. Illinois River Hoopnetting Summary 

(1978 5 79) 19-43 

Table 19-7. Spearman Rank Correlation Coefficients 
for Electrof ishing Catch vs. Average 
Water Levels, La Grange Pool 1959-1975 , 19-92 

APPENDICES 

APPENDIX A: PHYSICAL AND WATER QUALITY EFFECTS 

Table A- 1 . Increase (in feet) in Average Weekly Water 
Levels due to Diversion Rates of 6,600 cfs 
at Starved Rock, Henry, and Havana . . , A-1 

Table A-2. Increase (in feet) in Average Weekly Water 
Levels due to- Diversion Rates of 10,000 cfs 
at Starved Rock, Henry, and Havana , . , A-3 

Table A-3. Predicted Average River Velocities (ft/sec) 

Associated with Maximum Discharges, 1977 A-5 



Page 

APPENDIX B: METRIC EQUIVALENTS OF TABLES PRESENTED 
IN CHAPTER 4; INCLUDING SURFACE AREA, VOLUME AND 
AREA OF MUD FLATS OF VARIOUS BOTTOMLAND LAKES IN THE 
ILLINOIS WATERWAY 

Table B-1. Surface Area (Hectares) and Volume 

(Cubic Meters) of Selected Bottomland 
Lakes in the Peoria Pool (above Peoria 
Lake) based on 15-cm Contour Intervals 
below the 1978 Tree Line B-1 

Table B-2. Surface Area (Hectares) and Volume 
(Cubic Meters) of Upper Peoria Lake 
(Peoria Pool) based on 15- and 30- 
cm Contour Intervals below Normal Pool 
Elevation B-4 

Table B-3. Surface Area (Hectares) and Volume 

(Cubic Meters) of Selected Bottomland 

Lakes in the La Grange Pool based on 15-cm 

Contour Intervals below the 1978 Tree 

Line B-5 

Table B-4. Surface Area (Hectares) and Volume 

(Cubic Meters) of Selected Bottomland 

Lakes in the Alton Pool from La Grange 

to Grafton, Illinois based on 15-cm 

Contour Intervals below the 1978 Tree 

Line B-9 

Table B-5. Surface Area (Hectares) and Volume 

(Cubic Meters) of the Bottomland Lakes 
in the Entire Illinois River Valley, 
Utica to Grafton, Illinois, based on 15- 
cm Contour Intervals below the 1978 Tree 
Line B-10 

Table B-6. The Number of Hectares of Mud Flats Ex- 
posed on Certain Lakes of the Peoria 
Pool in Relation to Mean Sea Level River 
Stages at Henry for the Entire Growing 
Season of 10 July-1 October, 1959-1978 . B-12 

Table B-7. The Number of Hectares of Mud Flats Ex- 
posed in Certain Lakes of the La Grange 
Pool in relation to Mean Sea Level River 
Stages at Havana for the Entire Growing 
Season of 10 July-1 October, 1939-1978 . B- 1 5 

APPENDIX C: ANNOTATED SPECIES LISTS OF THE FLOR.'V AND 
FAUNA IN THE PROJECT AREA 

Table C-1. List of Trees in the Project Area .... C-2 

Table C-2. List of Shrubs in the Project Area . . . C-7 

Table C-3. List of Forbs in the Project Area .... C-10 

Table C-4. List of Grasses in the Proiect Area . . . 0-2" 



Page 

Table C-5. List of Emergent Plants in the Project 

Area C-30 

Table C-6. List of Submergent Plants in the Project 

Area , C-32 

Table C-7. List of Floating Aquatic Plants in the 

Project Area C-34 

Table C-8. List of Moist-Soil Plants in the Project 

Area , C-35 

Table C-9. List of Birds in the Project Area .... C-38 
Table C-10. List of Mammals in the Project Area . . . C-69 
Table C- 1 1 . List of Amphibians and Reptiles in the 

Project Area C-75 

Table C-12. Potential Fish Fauna of the Illinois 

Waterway C-85 

Table C-13. List of Threatened and Endangered Species 

in the Project Area C-94 

APPENDIX D: LIST OF PRIVATE LICENSED WATERFOWL 
HUNTING CLUBS 

Table D-1. Licensed Private Duck Hunting Clubs in 

the Project Area D-1 

Table D-2. Licensed Private Goose Hunting Clubs in 

the Project Area D-10 

APPENDIX E: ALGAE (PERIPHYTON AND PHYTOPLANKTON) 

Table E- 1 . Densities of Phy toplankton >*ajor Divi- 
sions and Total Phy toplankton Collected 
at 13 Sampling Stations during July, 
August, and September 1978 in the Illinois 
Waterway , . . . E-1 

Table E-2. Densities of Periphyton Major Divisions 
and Total Periphyton Collected at 13 
Sampling Stations during August and 
September 1978 in the Illinois Waterway . E-49 

Table E-3. Densities of Phy toplankton Taxa Col- 
lected at 13 Sampling Stations during 
July, August, and September 1978 in the 
Illinois Waterway E-53 

Table E-4. Densities of Periphyton Taxa Collected 
at 13 Sampling Stations during August 
and September, 1978 in the Illinois 
Waterv,'ay . ■ , , . , E-lli 



Page 



APPENDIX F; 
Table F-1 . 



Table F-2. 



APPENDIX G; 

Table G- 1 . 
Table G-2. 



Table G-3. 

Table G- 4 . 

Table G-5. 

Table G-6. 
Table G-7. 

Table G-8. 
Table G-9. 



ZOO PLANKTON 

Predominant Forms of Rotifera, Cladocera, 
and Copcpoda Collected at 12 Sampling 
Locations in the Illinois River Water- 
Avay and at One Location in Pool 26 of the 
Mississippi River, July, August, and 

September 1978 F-1 

Abundance of Zooplankton at 12 Stations 

in the Illinois Watenvay and 1 Station 

in Pool 26 of the Mississippi River, July, 

August and September 1978 F-6 

FISH 

Locations of 1976 Inventory Stations . . G- 1 
Summary of Illinois Waterway >Unnow 
Seining, Hoop-netting, and Electro- 
fishing Stations, 1971-1979 G-4 

Numbers of Fishes Collected from Lake 
Michigan Sites during 1976 by the Metro- 
politan Sanitary District of Greater 

Chicago , G-10 

Numbers of Fishes Collected from North 
Shore Channel Sites during 1976 by the 
Metropolitan Sanitary District of Greater 

Chicago G-11 

Numbers of Fishes Collected from North 
Branch Chicago River sites in the Illinois 
Waterway during 1976 by the Metropolitan 
Sanitary District of Greater Chicago . . G- 1 2 
Numbers of Fishes Collected from Chicago 
River Sites during 1976 by the Metropoli- 
tan Sanitary District of Greater Chicago G- 1 3 
Numbers of Fishes Collected from South 
Branch Chicago River Sites during 1976 by 
the Metropolitan Sanitary District of 

Greater Chicago G-14 

Numbers of Fishes Collected from Chicago 
Sanitary and Ship Canal Sites in the 
Illinois Waterway during 1976 by the 
Metropolitan Sanitary District of Greater 

Chicago G-15 

Numbers of Fishes Collected from Calumet 
River Sites in the Illinois Waterway 
during 1976 by the Metropolitan Sanitary 
District of Greater Chicago G-16 



XIX 



Page 

Table G-10. Numbers of Fishes Collected from Little 
Calumet River Sites in the Illinois 
Watenvay during 1976 by the ^'etropoli tan 
Sanitary District of Greater Chicago . . G-17 

Table G-11. Numbers of Fishes Collected from Calumet- 
Sag Channel Sites in the Illinois Water- 
way during 1976 by the Metropolitan 
Sanitary District of Greater Chicago . . G-18 

Table G-12. Numbers of Fishes Collected from 

Dresden Island Pool Sites in the Illinois 
Waterway during 1976 by the Metropolitan 
Sanitary District of Greater Chicago . . G-19 

Table G-13. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Alton Pool of the Illinois 
River and 2 Mississippi River Stations 
during the Summer of 1978 G-23 

Table G- 1 4 . Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the La Grange Pool of the Illi- 
nois River during the Summer of 1978 . . G-25 

Table G-15. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Peoria Pool of the Illinois 
River during the Summer of 1978 G-28 

Table G-16. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Starved Rock Pool of the 
Illinois River during the Summer of 1978 G-30 

Table G-17. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Marseilles Pool of the 
Illinois River during the Summer of 1978 G-31 

Table G-18. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Dresden Pool of the Des 
Plaines River during the Summer of 1978 . G-32 

Table G-19. Summary of the 15-Pace, 20-Foot Minnow 
Seine Hauls in the Alton Pool of the 
Illinois River during the Summer of 1979 G-33 

Table G-20. Summary of the 15-Pace, 20-Foot Minnow 

Seine Hauls in the La Grange Pool of the 
Illinois River during the Summer of 1979 G-35 

Table G-21. Summary of the 15-Pace, 20-Foot Minnow 
Seine Hauls in the Peoria Pool of the 
Illinois River during the Summer of 1979 G-37 

Table G-22. Summary of the 15-Pace, 20-Foot >?innow 
Seine Hauls in the Starved Rock Pool of 
the Illinois River during the Summer of 
1979 G-39 

Table G-23. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Marseilles Pool of the 
Illinois River during the Summer of 1979 G-40 

Table G-24. Summary of 15-Pace, 20-Foot Minnow Seine 
Hauls in the Dresden Pool of the Des 
Plaines River during the Summer of 1979 , G-42 



XX 



Page 

Table G-25. Summary of Hoopnetting in the Alton 
Pool of the Illinois River during 
1978-1979 G-43 

Table G-26. Summary of Hoopnetting in the La Grange 
Pool of the Illinois River during 
1978-1979 G-45 

Table G-27. Summary of Hoopnetting in the Peoria 
Pool of the Illinois River during 
1978-1979 G-47 

Table G-28. Summary of Hoopnetting in the Starved 
Rock Pool of the Illinois River during 
1978-1979 G-Sn 

Table G-29. Summary of Hoopnetting in the Marseilles 
Pool of the Illinois River during 1978- 
19 79 n-5 2 

Tables G-30 to G-54. Electrof ishing Results .... G-54 
(to be added) 

APPENDIX H: LIST OF PERSONNEL CONTACTED FOR INFOR- 
f'ATION UTILIZED IN THIS REPORT 

Table H- 1 . List of Personnel Contacted for Infor- 
mation Utilized in Terrestrial Environ- 
ment Section H- 1 



XXI 



LIST OF FIGURES 

Page 

Figure 1-1. The drainage basin of the Illinois 

Waterway 1-2 

Figure 1-2. The history of diversion of Lake 
Michigan water into the Illinois 
Waterway 1-4 

Figure 2-1. Simulated weekly water level increases 
that would have occurred at Starved 
Rock, Henry and Havana during water 
years 1971, 1973 and 1977 under the 
proposed 6,600-cfs increased diversion 
rate 2-4 

Figure 2-2. Simulated weekly water level increases 
that would have occurred at Starved 
Rock, Henry and Havana during water 
years 1971 and 1977 at the proposed 
10,000-cfs diversion rate 2-5 

Figure 2-3. Predicted dissolved oxygen concentra- 
tions in the Upper Illinois Waterway at 
discretionary diversion rates of and 
3250 cfs 2-9 

Figure 2-4. Mean and maximum turbidities in Jackson 
Turbidimeter Units, in the Illinois 
Waterway 2-10 

Figure 2-5. Illinois Waterway mean ambient tempera- 
tures (with ranges) during 1971 , . . ,2-13 

Figure 3-1. Pool regions of the Illinois and Mis- 
sissippi rivers evaluated in this 
report 3-2 

Figure 4-1. Bottomland lakes along the Illinois 

River selected for depth transects . . 4-19 

Figure 4-2. Average weekly water levels at Havana 

1958-1978 4-21 

Figure 5-1. Bottomland forest study areas located 
within the project boundaries of the 
Illinois River valley , . 5-19 

Figure 5-2. Moist-soil plant study areas at Rice 

and Spring. Lakes 5-67 

Figure 9-1. Localities within the project area 

censused for shorebirds 9-4 



XXll 



Page 

Figure 10-1. Heron colonies located within the 
project area in the Illinois River 
valley 10-5 

Figure 12-1. Summer breeding bird census and Audubon 
Christmas bird count locations within 
the project area of the Illinois River 
valley 12-7 

Figure 14-1. State parks, state conservation areas, 
and federal wildlife areas located 
within the project area of the Illinois 
River valley 14-3 

Figure 14-2. Nature preserves located within the 
project area of the Illinois River 
valley 14-5 

Figure 14-3. Natural areas located within the project 

area of the Illinois River valley . . . 14-8 

Figure 16-1. Chicago Area Waterways. Plankton and 

Periphyton Sampling Stations 16-13 

Figure 16-2. Illinois Waterway. Plankton and Peri- 
phyton Sampling Stations 16-14 

Figure 17-1. Cluster analysis of zooplankton sampled 

from the Illinois Water\vay in July 1978 17-25 

Figure 17-2. Cluster analysis for zooplankton sampled 
from the Illinois Watenvay in August 
1978 17-26 

Figure 17-3. Cluster analysis for zooplankton sampled 
from the Illinois Waterway in September 
1978 17-27 

Figure 18-1. Location of stations in the Illinois 

River where Anderson (1977) took bottom 
samples in the fall of 1975 18-3 

Figure 18-2. Location of stations in the Chicago 

area waterways where biologists from the 

Metropolitan Sanitary District of 

Greater Chicago took bottom samples in 

the summer, fall, and winter of 1975 . 18-5 

Figure 18-3. Dissolved oxygen levels in the Illinois 
River in the summers of 1965 and 1966 
and the numbers of mussels caught per 
5 minutes of fishing with the crow- 
foot bar in 1966 18-15 

Figure 18-4. The number of kinds of mussels in the 

Illinois River in 1912 and in 1966-1969 18-16 

Figure 18-5. Maximum ammonia concentrations in the 

Illinois River in 1967 18-18 



Page 

Figure 18-6. Illinois Environmental Protection 

Agency classification of the Illinois 
River in 1967 and 1978, based on the 
percentage of -nol lution- tolerant , 
intolerant, moderate, and facultative 
drift organisms occurring on artificial 
substrates 18-24 

Figure 18-7. The number and kinds of drift organisms 
colonizing artificial substrates in 
the Illinois River, and the lEPA clas- 
sification, based on drift organisms . 18-25 

Figure 19-1. Locations of 10 watershed subunits of 
the upper Illinois Waterway, Cook, 
DuPage, and Will Counties, Illinois . . 19-3 

Figure 19-2. Illinois Waterway electrof ishing sta- 
tions, 1978-1979 19-8 

Figure 19-3. Illinois Waterway minnow seine stations, 

1978 ' 19-9 

Figure 19-4. Illinois Waterway 1978 and 1979 hoop- 
netting stations 19-11 

Figure 19-5. Effect of present diversion on upper 
Illinois W^aterway, Cook, DuPage, aid 
Will Counties, Illinois 19-51 

Figure 19-6. Summary of environmental quality, upper 
Illinois Waterway, Cook, DuPage, and 
Will Counties, Illinois 19-52 

Figure 19-7. Historical Lake Michigan diversion 

rates, water levels at Havana, Illinois, 
commercial fish yields from the 
Illinois River, and licensed commercial 
Illinois River fishermen 19-55 

Figure 19-8. Illinois River electrof ishing results 

for goldfish, 1959-79 19-58 

Figure 19-9. Illinois River electrof ishing results 

for largemouth bass, 1959-79 19-59 

Figure 19-10. Illinois River electrof ishing results 

for black bullhead, 1959-79 19-61 

Figure 19-11. Illinois River electrof ishing results 

for carp, 1959-79 19-63 

Figure 19-12. Illinois River electrof ishing results 

for white bass, 1959-79 19-66 

Figure 19-13. A main channel border minnow-seine 
station in the Peoria Pool at River 
Mile 229.4 19-68 

Figure 19-14. A main channel border minnow-seine 

station in the Peoria Pool just below 

the "great bend" at River Mile 207 . . 19-69 



Page 

Figure 19-15. A bottomland lake (Sawmill Lake) minnow- 
seine station in Peoria Pool, River 
Mile 197 19-70 

Figure 19-16. Percentage of total catch for eight 
species or groups from four hoop- 
netting surveys of the Illinois River 19-73 

Figure 19-17. Illinois River electrof ishing results 

for channel catfish, 1959-79 19-76 

Figure 19-18. Inverse relationship of increasing 
percentage of diversion flow to de- 
creasing toxicity values for the North 
Shore Channel 19-84 

Figure 19-19. Inverse relationship of increasing 
percentage of diversion flow to de- 
creasing toxicity values for the 
Chicago River ..... 19-85 

Figure 19-20. Inverse relationship of increasing 
percentage of diversion flow to 
decreasing toxicity values for the 
Calumet River 19-86 

Figure 19-21. Inverse relationship of increasing 
percentage of diversion flow to 
decreasing toxicity values for the 
Little Calumet River 19-87 

Figure 19-22. The relationship observed between 
1894 and 1914, between commercial 
fish production in the Illinois River 
and water surface area covered more 
than half of the year 19-91 



SECTION I 
INTRODUCTION 



1-1 



CHAPTER 1 : PURPOSE AND SCOPE 



DESCRIPTION OF THE ILLINOIS WATERWAY 




"The Illinois Waterway extends from the Missis- 
sippi River, 61.2 km (38 mi) above St. Louis, Missouri, 
to Chicago, Illinois, a distance of 524.6 km (326 
mi) (Figure 1-1). It provides a commercially 
navigable connection between the St. Lawrence- 
Great Lakes and the Mississippi-Ohio Rivers navi- 
gation systems. The waterway is completely chan- 
nelized and includes the following segments: the 
Illinois River from its mouth at Grafton, Illinois, 
to the confluence of the Kankakee and Des Plaines ^ 3"^ '? |>L 
Rivers, a distance of 439.3 km (273 mi); the Des 
Plaines River to Lockport lock, a distance of 29.1 
km (18.1 mi); the Chicago Sanitary and Ship Canal 
to Calumet-Sag Junction, a distance of 20.0 km 
(12.4 mi), and the Calumet-Sag Navigation Project, 
Part I, which provides a connection to the deep- 
draft project at Lake Calumet and the upper limit 
of Calumet Harbor, via the Calumet-Sag Channel, the 
Little Calumet River and the Calumet River, a total 
distance of 38.3 km (23.8 mi). An alternative route 
to Lake Michigan is also provided from Calumet-Sag 
Junction to Chicago Harbor via the Chicago Sanitary 
and Ship Canal and the Chicago River, a distance of 
35.6 km (22.1 mi). A further connection, authorized 
by Congress but not constructed, is provided by Part 
II of the Calumet-Sag Project which connects the 
Little Calumet River to the deep-draft Indiana Har- 
bor, via the Grand Calumet River and Indiana Harbor 
Canal, involving a distance of 19.3 km (12 mi). The 
width of the existing channel between Grafton and 
Lockport, Illinois, is 91.4 m (300 ft), except in 
the Marseilles Canal where it is 61.0 m (200 ft). 
The minimum width of the Chicago Sanitary and Ship 
Canal is 48.8 m (260 ft) and the width of the Calu- 
met-Sag Channel is 68.6 m (225 ft). The 2.7-m 
(9-ft) navigation depth in the Waterway is used 



Purpose 5 Scope 




O = INDICATES THE LOCATION OF CITIES 
• = INDICATES LOCK AND DAK SITES 



Figure 1-1. The drainage basin of the Illinois Watervcay 



Purpose 5 Scope ^ 



almost exclusively for commercial barge navigation 
with the principal commodities transported being 
coal, petroleum, grain, sand, gravel, and miscellan- 
eous freight. Navigation on the Illinois Waterway 
tributaries is limited to recreational boats." 
(Bellrose et al., 1977: A-1) 

The Illinois is a sluggish river resulting from a 
nearly level channel with a low rate of fall and a relatively 
small volume of water (Mills et al., 1966: 3). The fall of 
the upper river from Lockport to Starved Rock is approximately 
11 times greater than the fall in the remaining 371.7 km 
(231 mi) from Starved Rock to Grafton. Because of the 
greater rate of fall, the waterway from Lockport to Starved 
Rock has steep banks with very few backwater areas. How- 
ever, from Hennepin south to Grafton, the Illinois River 
enters the ancient valley of the Mississippi River. In 
this section, the river falls more slowly and forms thousands 
of acres of bottomland lakes. "The river, flowing in its 
unusually wide valley and carrying a silt load, drops more 
of this silt at the quieter edges than in the more rapid 
stream center. This builds up low natural levees along its 
shores. Overflow of the river at high water leaves large 
impoundments behind these levees as the water recedes. 
Usually these impoundments are shallowly connected with the 
river at their upper and lower ends." (Mills et al., 1966: 
3) . These impoundments or bottomland lakes and the adjacent 
bottomland terrestrial communities provide valuable habitat 
for fish and wildlife. 

Lake Michigan and the Illinois River were first joined 
in 1848 when the Illinois and Michigan Canal was construc- 
ted for navigational purposes. The actual diversion of 
water from Lake Michigan, however, was limited until 1871 
when the canal was deepened and the flow of the Chicago 
River was reversed. Figure J=^^ portrays the history of 
diversion of Lake Michigan water into the Illinois Waterway. 
Pumping between 1894 and 1900 helped increase the diversion 
rate to as much as 1,000 cubic feet per second (cfs) through 
the canal which emptied into both the Des Plaines River at 
Joliet and the Illinois River at La Salle (Starrett, 1972: ^ 
145). Completion of the Chicago Sanitary and Ship Canal in -^' 
1900 allowed major diversion of Lake Michigan water down the / 
Illinois Waterway. ^y 



From 1900 to the present, the Illinois Waterway has 
experienced several changes in the amount of water diverted 
from Lake Michigan (Figure 4—2-) . From 1900 to 1938 the 
diversion ranged from 2,900 cfs to 10,010 cfs with an 
average of 7,222 cfs for this 39-year period. A U.S. 



r^~- 



Purpose 5 Scope 



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Purpose 5 Scope 1-5 

Supreme Court decree limited diversion to 1,500 cfs in addition 
to domestic pumpage after 1938 (the total usually amounted to 
approximately 3,100 cfs). A 1967 decree limited the diversion 
(including domestic pumpage) to an average of 3,200 cfs over a 
five-year period (Corps of Engineers, 1978: 7). 

/pams constructed between 1933 and 1939 maintained "^ 
water levels during low flows to provide a channel depth 
of at least 2.7 m (9 ft) for navigation. During periods of 
low rainfall the river presently does not drop as low as 
it did prior to construction of the dams. Because of the 
relatively rapid rate of fall in the river above Starved 
Rock, the lifts of the dams in this area range from 5.6 m 
(18.5 ft) to 11.9 m (39 ft) as compared to the Peoria and 
La Grange dams that have lifts of only 3.4 m (11 ft) and 
3.0 m (10 ft), respectively. 

THE PROJECT 



The Water Resources Act of 1976 authorized the Secre- 
tary of the Army, acting through the Chief of the Engineers, 
to implement a five-year demonstration program to increase 
the average annual Lake Michigan diversion at Chicago from 
the present limit of 3,200 cfs up to 10,000 cfs. The act 
also directed the Corps of Engineers to conduct a study and 
a demonstration to determine the effects of the increased 
diversion on the levels of the Great Lakes, on the water 
quality of the Illinois Waterway, on the susceptibility of 
the Illinois Waterway to additional flooding, and to inves- 
tigate any other adverse or beneficial impacts which may 
result . 

The objective of this study was to document and evalu- 
ate the present quality and quantity of the fish and wild- 
life resources of the Illinois Waterway including a portion 
of Pool 26 of the Mississippi River in enough detail to (1) 
predict the probable impacts on aquatic and terrestrial 
communities of increased Lake Michigan diversion at an 
annual average rate of 6,600 cfs and 10,000 cfs, and (2) es- 
tablish current baseline biological conditions of the 
Waterway for future comparisons. 



2-1 



CHAPTER 2: PHYSICAL AND WATER QUALITY CHANGES 
ASSOCIATED WITH INCREASED DIVERSION 



INTRODUCTION 



In order to predict the possible biological effects of 
increased diversion, it vas necessary to estimate the magni- 
tude and seasonal nature of the physical and water quality 
changes in the Waterway that would result from the proposed 
increased diversion rates. Several physical and water quality 
parameters were considered because of their probable or poten- 
tial influence on the biological resources of the V.'aterway. 
These parameters are outlined in Table 2-1. The rest of this 
chapter describes each of these param.eters separately, and 
discusses how we estimated the effects of diversion on them. 



PHYSICAL CHANGES 

Absolute Water Levels 

Future changes in water levels along the Waterway which 
would result from increased diversion were estiniated by 
analyzing comiputer-generated stage hydrographs provided by 
the Chicago District, Corps of Engineers. These hydrographs 
were generated by a hydraulic model of the Waterway using 
actual water level data from, water years 1971 (considered an 
intermediate- flow year), 1973 (a high-flow year), and 1977 
(a low-flow year). The hydrographs indicated water levels 
at 17 gauge stations for each of three average annual diversion 
rates: 3,200 cfs (the present rate), 6,600 cfs, and 10,000 
cfs. The model used the same daily and seasonal control 
programs that are expected to be used during the actual increased 
diversion project. These control programs, however, were 
not in use during the years 1971, 1973 and 1977, and as a 



Physical 5 V.'ater Quality 



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Physical 5 Water Quality 2-3 



result the simulated hydrographs that represented the 3,2C0-cfs 
diversion rate did not exactly match the actual water levels 
that Kere fed into the model. The differences between the 
simulated water levels for the different diversion rates were 
considered to be the best available estimates of the effects 
of increased diversion on water levels in the Waterway and 
were used to calculate average weekly water level increases 
at three locations on the V.'aterway: Starved Rock, Henry, and 
Havana (Appendix A, Tables A-1, A- 2) . The weekly average 
water level increases (above 3,200 cfs) at these locations 
resulting from increased diversion rates of 6,600 cfs and 
10,000 cfs were plotted in Figures 2-1 and 2-2, respectively. 
The Starved Rock gauge (located directly below the lock) was 
selected to indicate the miaximum water level changes that are 
expected in the Illinois River. The Henry and Havana gauges, 
v;hich are located near the midpoints of their respective pools 
(Peoria and La Grange), were selected to reflect water level 
changes within these pools. The water level changes at 
Henry and Havana were subsequently used to estimate volume 
and surface area changes in the Illinois River and its backwaters 
(see Chapter 4) . 

Water Level Stability 

The effects of increased diversion on water level stability 
in the Waterway were assessed using the same hydrographs 
described above. Water level stability was defined using several 
time intervals because aquatic organisms can be affected differ- 
ently by short and long term fluctuations. Water level fluctu- 
ations were evaluated using the data in Appendix A, Tables A-1 
and A-2, (described earlier). 

Velocity 

Predicted average river velocities during maxinum dis- 
charge periods for the 3 diversion rates during 1977 were 
calculated by Bhowmik and Schicht (1979: 65-69), using Chicago 
District, Corps of Engineers hydrographs of water levels and 
discharge. Velocities associated with maximum discharges were 
listed for 19 river locations (Appendix A, Table A-3). In 1971 
and 1975, they noted no differences in simulated maximum dis- 
charges at these locations under different diversion rates and 
therefore only single velocity values were calculated for these 
years. It should be emphasized, therefore, that these estimates 
were limited in that they only indicated velocity increases 
associated with maximum river discharge events. 



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Physical 5 V.'ater Quality 2-6 



Velocities in the backwater areas characteristic of the ; 
middle and lower portions of the waterway probably are not i| 
well represented by these values. Based on results generated by' 
a backwater model for the Illinois River near Peoria, the Chicag( 
District Corps of Engineers (1975: 17) predicted that there couli 
be an increase in velocity of about 15 percent resulting froni 
increased diversion during nonflood conditions. However, the 
locations at which this increase was predicted were not 
specified . 



WATER QUALITY CHANGES 

The water quality of Lake Michigan is dramatically differen 
in a number of ways than that of the Illinois Waterway (Table 
2-2). Increased diversion of this relatively clean water is 
likely to produce changes in several water quality parameters 
in the Waterway and, in general, these changes will be most 
pronounced at the upstream ends of the Waterway and decrease 
in magnitude with distance downstream.. The primary water ! 
quality parameters that could influence the aquatic life in ! 
the Waterway are (1) dissolved oxygen, (2) suspended sediment i 
content and turbidity, (3) toxic materials, (4) tem.perature , ' 
and (5) mineral and nutrient content. 

Dissolved Oxygen 

Dissolved oxygen (D.O.) is critically important to aquatic 
life in the Illinois Waterway. Increased diversion of Lake 
Michigan water into the Waterway could increase the concen- 
trations of D.O. in the upper reach of the Waterway because 
of the higher concentrations of D.O. normally present in Lake 
Michigan and because increased flows will probably result in 
increased aeration of the water once it enters the V.'aterway. 

The Metropolitan Sanitary District of Greater Chicago 
has m.odeled the effects of two discretionary diversion rates, 
and 3,250 cfs, on the dissolved oxygen concentration of the 
Waterv;ay from the Lake >tichigan control structures downstream | 
to Chillicothe, Illinois (Department of the Army, Corps of 
Engineers, 1979: 135). Discretionary diversion is the flow j 
over which the District can exercise control (i.e., exclusive | 
of domestic pumpage, stormwater runoff, leakage, and flow j 
required for lockages and navigat ion) (Macai tis et al., 1977: ] 
795). For instance, during the accounting year 1975, non- 
discretionary diversion flow equaled 2,919 cfs, leaving only 
281 cfs left over (3,200-2,919 cfs) for discretionary diversion 
to improve water quality in the Waterway. Summer dry weather 



Physical 5 Water Quality 2-7 



Table 2-2. Mean Concentrations of Certain V.'ater Quality 
Constituents (mg/1) . ^ 









Illinois Waterway 






Lake Michigan 
0.3 


at Peoria 


Turbidity (JTU) 


49 


Total Dissolved Sol: 


ids 


165 


412 


Hardness (CaCOj) 




135 


279 


Alkalinity (CaC03) 




115 


169 


Sulfate (SO4) 




24 


109 


Chloride (CI) 




8 


40 


Ammonia (NH3-N, total) 


0.01 


0.6 


Nitrate (NO3) 




1 


15 


Phosphorus (PO4) 




0.05 


2.6 


Maximum Summer 








Temperature C°C) 




22.2 


32.2 



^ Taken from Chicago District, Corps of Engineers (1979: 100) 



Physical 8, Water Quality 



2-8 



tha? at ?h.i 7?n^ vere used in the niodel, vs^hich indica 
rn^l I ^ '"^ ""l^ discretionary rate, dissolved oxy 
concentrations in the Waterway would be (a) increased i 
Capproximately 1.5 mg/l) in the pools nearer Chicago th 
those downstream Capproximately 0.5 mg/1) and (b) would 
increased more m the downstream reach of each pool tha 
tJ V^rro" '"^^^^- ^^2"^^ 2-3 shows the results of th 
;°^4^^,S-0; concentration vs. distance. We have assum 
J?!/' 1?"''^ discretionary flow rate approximates cond 
that will result from the proposed 6,600-cfs increased 
diversion rate. 

It should be noted here that the MSDGC and Harza E 
have predicted the amount of total annual diversion tha 
be needed to maintain D.O. standards (as established by 
Jk i;?nrr^ °-^^''^'°" Control Board) in the Waterway befor 
the MSDGC mstream aeration system becomes established 
(Department of the Army, Corps of Engineers, 1979: 146 
Tnese values which were simulated based on 1975 conditi 
were 5,500 cfs (MSDGC) and 4,800 cfs (Harza Engineering 
ettects of the mstream aeration system may substantial 
tluence the relationship between increased diversion an 
D.O. m the Waterway in the future. 



ted 
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Suspended Sediment and Turbidity i 

■ — ,j 

vni-}. In^^''^'^^ '!?.^^^ Illinois Waterway generally increases i 
Va^ tJ ''"f ^^stance downstream from Lake Michigan (Figure ' 
2-4). This relationship is for the m.ost part a result of 
sediment loads carried into the Waterway from tributary streams 
and the presence of commercial barges on the Waterway which ' ' 
continually resuspend bottom sediments in the main channel 
Below Starved Rock Lock and Dam, sediment deposits have fifled 

sauce? 1 k^ ^^^^^^^^^ 1^^^1,^° Jh-t they are now only ^hailow; ■ 
saucer-like depressions. The shallow waters of these lakes : 
are almost continuously turbid because wave action, and (usually 
to a lesser extent) the activity of bottom-feeding fish 
resuspend bottom sediments. 

.bin h^t^""^ ^°^ able to confidently estimate a constant relation 

V'at^rv^v ?),'''''^^^w'^-^'''^'"'^°" ^^^ turbidity levels in the 
waterway. The slight increases in velocity (Appendix A 
lable A-3) that will accompany increased diversion will'also 

Abrun?'ch.^Lr''"J^'^ °^ '^' "^"^" ^^"^'^^l ^° "^^V sediment. 
Abrupt changes in diversion rates should produce temporary 

increases in turbidity as bottom sediments are transported 
thr? u^h'' ^'' °^^"^^ed in the upper part of the Wa^?way during 
the flushing experiment in 1940 (Corps of Engineers, 1979: ^ 
faJtors^^nn^T'^^''' ^^^b^d^ty is also related to many other 
factors such as precipitation and subsequent soil erosion and 



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Physical 5 Water Quality 



2-10 



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m 

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z: 

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z: 



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Physical 5 Kater Quality 2-11 



run off, wind and wave action, the presence of planl;ton, and 
the activity of hot toni- feeding fish, each of which under 
different circun'stances can influence sediment suspension 
and/or turbidity to a g^reater extent than the predicted 
increases in velocity. For these reasons, we have made no 
general assumption about the effects of increased diversion 
on sediment and turbidity in the Waterway but have attempted 
to consider, when appropriate, the effects of increased di- 
version under different conditions of turbidity or suspended 
sediment . 



Toxic ''Materials 



Numerous substances that are considered toxic to aquatic 
organism.s have been found in the Illinois Waterway by the 
Illinois Environmental Protection Agency (Corps of Engineers, 
1979: 8-15; Lubinski et al., 1975). Som.e of these, such as 
am.monia and heavy metals, occur more often and at higher 
concentrations in the Chicago- Joliet and Peoria-Pekin areas 
than in downstream reaches as a result of municipal or indus- 
trial sources (Corps of Engineers, 1979: 15). Others, such 
as cyanide, occur periodically at relatively isolated loca- 
tions (Lubinski, 1975). Trace amounts of agriculture- 
related compounds such as Aldrin and Dieldrin have also been 
found in the V.'aterway or in organisms living in the waterway 
(Lubinski, 1975; Walter and Sparks, unpublished data). 
Increased Lake Michigan diversion will result in the dilution 
of some of these materials, particularly those originating 
in the Chicago- Joliet area from point sources. In order to 
predict how m.uch dilution will occur, Bluegill Toxicity Indices 
were calculated for several Chicago-area Waterway stations under 
different diversion rates (see Chapter 19). In addition, the 
increased flow in the Waterway will carry these materials 
further downstream than they are presently carried but 
should have no effect on the overall load of these materials 
to the V.'aterway. 

Many toxic substances are bound to sediment particles, 
and may be relocated if the sediments are resuspended and 
Fioved by increased diversion. Once again, however, the con- 
sequences of such activities are dependent on a number of 
variables (see above section on Suspended Sediment and Tur- 
bidity) and cannot be predicted at this time. 

Temperature 

Lake Michigan water temperatures are more stable through- 
out the year than are temperatures in the Waterway. Since 
the water temperature of Lake Michigan is much lower than 



Physical 5 Water Quality 2-12 



the temperature of the Waterway in the summer, increased 
diversion will probably result in temperature reductions in 
the upper Waterway, although no predictions have been found 
regarding the magnitude of this reduction. The upper Water- 
way, however, is already subject to increased temperatures, 
produced by power plant thermal effluents and municipal 
sewage effluents (Figure 2-5). Reductions in upper Water- 
way temperatures will probably have minimal effects on the 
aquatic resources of the Waterway per se, but may improve 
the dissolved oxygen capacity of the Waterway. 



General Mineral Content 



The effects of increased diversion of Lake N!ichigan 
water on the mineral content (including dissolved solids, 
alkalinity, hardness, chloride, nitrate, and total phosphorus 
concentrations) has been estimated by the Illinois State 
Water Survey using a model which was based on statistical 
inter-station relationships for each parameter (Illinois 
State Water Survey, 1979). In general, their results 
indicated that diversion-related effects were primarily 
limited to those reaches of the V.'aterway above mile 220 
(La Salle-Peru) . They concluded (a) that diversion-related 
changes in mineral content of the Waterway would not affect 
the osmotic balance of the Waterway's fauna and flora, and 
(b) that the diversion of Lake Michigan water would generally 
improve the chemical quality of the Waterway. 



Physical 5 l\'ater Quality 



2-13 



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SECTION II 
TERRESTRIAL ENVIRONMENT 



3-1 



CHAPTER 3: INTRODUCTION TO WILDLIFE STUDIES 



In order to assess the terrestrial effects of increased 
diversion on the Illinois Waterway, we divided the river into 
the following four sections (Figure 3-1): (1) the Upper 
Pools extend from the beginning of the Waterway at Lake 
Michigan in Chicago to the Starved Rock Lock and Dam at 
river mile 231,0; (2) Peoria Pool extends from the Starved 
Rock Lock and Dam to the Peoria Lock and Dam at river mile 
157.7; (3) La Grange Pool extends from the Peoria Lock and 
Dam to the La Grange Lock and Dam at river mile 80.2; and 
(4) Alton Pool begins at the La Grange Lock and Dam and 
ends at Lock and Dam No. 26 in the Mississippi River at 
Alton, Illinois. 

The Illinois Waterway from Chicago to Starved Rock is 
heavily populated and has limited backwater areas and other 
riparian habitat available to wildlife. For this reason, 
many of our analyses of increased diversion will be con- 
centrated on the section of the Illinois River from 
Starved Rock to Alton that encompasses the Peoria, La 
Grange, and Alton pools. 

Results from a computer model of the proposed increased 
diversion schemes were provided by the Corps of Engineers, 
Chicago District, for use in evaluating potential diversion 
effects (see Chapter 2 for description of the computer 
model). Computer predictions of water levels and readings 
from two river gauges located at Henry and Havana were 
used to investigate the terrestrial effects of the increased 
diversions. These two stations were chosen because they 
are located near the middle of the Peoria and La Grange 
pools, respectively, and thus reflect the changes in water 
levels in these pools (Figure 3-1). 

Average weekly gauge readings from the baseline, 6,600- 
cfs, and 10,000-cfs diversion rates were calculated from 
the predicted daily gauge readings provided by the computer 
model beginning with 1 October for the three years 1971, 
1973, and 1977. These weekly averages were then used to 
calculate average predicted readings for the entire year 
and for the following critical growing seasons: (1) 30 April 




25 50 

MILES 



Figure 3-1. Pool regions of the Illinois and Mississippi 
rivers evaluated in this report. 



Wildlife Introduction 3-3 



through 1 October -- the growing season for aquatic plants 
(emergent, submergent , and floating), trees, shrubs, and 
herbaceous plants - - ; and (2) 10 July through 1 October -- 
the optimum period for moist-soil plants to germinate and 
produce a significant amount of seed. The predicted water 
levels at both the Henry and Havana gauges during the two 
growing seasons and the entire year are presented in 
Tables 5-1 and 3-2, respectively, for the 3,200- (baseline), 
6,600-, and 10,000-cfs diversion rates in 1971, 1973, and 
1977. 

Although the annual average water levels were highest 
in 1973, intermediate in 1971, and lowest in 1977, this 
situation changes if we consider only the two growing seasons 
For the 30 April-1 October growing season, 1971 exhibited 
the lowest water levels whereas 1977 had an intermediate 
and 1973 had the highest water level (Tables 3-1, 3-2). 
However, for the 10 July- 1 October period, water levels were 
the lowest in 1971, intermediate in 1973, and highest in 
1977. 

The simulated results from the computer model for the 
present baseline 3,200-cfs diversion rate differ slightly 
from the actual river gauge readings recorded by the U.S. 
Weather Service. Because of this discrepancy, we referred 
in our analyses to the differences between the predicted 
river levels at the baseline and the two proposed increased 
diversion rates rather than to the absolute predicted 
levels in mean sea level (msl). 

To evaluate the effects of the computer-modeled in- 
creased diversions, actual gauge readings for the two 
selected growing seasons during 1971, 1973, and 1977 were 
averaged from the river stages recorded by the U.S. Weather 
Service for Henry (Peoria Pool) and Havana (La Grange Pool) . 
These average gauge readings represent the actual water 
levels at the present diversion rate of 3,200 cfs without 
additional diversion. We then added the computer-model- 
predicted increases in water levels for the 6,600- and the 
10,000-cfs diversions to the actual average gauge readings 
to derive the river levels in msl if these diversion rates 
were implemented. 

The effects of increased water levels in the bottom- 
land lakes along the Illinois River are governed by their 
bottom contours. Sedimentation, especially in recent years, 
has filled in the once varied bottoms of these lakes and 
thus created the typical shallow backwater lakes of today 
that have uniform, platter-shaped bottoms. Therefore, even 
a minor change in water levels can inundate or expose 



Wildlife Introduction 



3-4 



Table 3-1. Predicted Average Gauge Readings in msl (ft) from 
the Computer Models for Henry (Peoria Pool) with 
No Additional Diversion, 6,600-cfs Diversion, and 
10,000-cfs Diversion. The Gauge Readings are for 
the Entire Year, and the Entire Growing Periods of 
30 April-1 October and 10 July-1 October, 1971, 
1973, and 1977. 



Year 

1971 

1973 
1977 

1971 

1973 
1977 

1971 

1973 
1977 



Predicted Average Predicted Average Predicted Ave: 

Gauge Reading Gauge Reading Gauge Readi| 

with No Additional at 6,600-cfs at 10,000-c 

Diversion, msl (ft) Diversion, msl (ft) Diversion, ms 



52 Weeks (365 Days) 



441 .4 



(1.2) 



442.6 
— I I 



445.9 



(0.6) 



-(2.2) 
446.5 



Cl.O) 



440.4 
I 



-(1.2)- 
I 



441 .6 
I I 



(2.3) 



(1.1)- 
I 



30 April-1 October (155 Days) 



440.0 
I 



(1.6)- 



441 .6 
I I 



443.7 



440.9 



-(1.4). 

-(1.7)- 
( 



-(3.0) 

445.1 
t 



(1.4)- 
I 



442.6 
— 1 1 



(2.6)- 



(0.9)- 
I 



10 July-1 October (83 Days) 



440.0 
I 



(1.0)- 
l 



441 .0 
I I 



440.2 
I 



441 .3 



•(2.5)- 
■(1.7)- 



-(2.7)_ 

442.7 
1 



(1.7). 



443.0 



■(2.8) 



(1.1)- 
I 



4 4 3.6 
I 



442.7 



443.0 
I 



443.5 
t 



442.7 



444. 1 
I 



Differences 



Wildlife Introduction 



3-5 



Table 3-2. Predicted Average Gauge Readings in msl (ft) from 

the Computer Models tor Havana CLa Grange Pool) vith 
No Additional Diversion, 6,600-cfs Diversion, and 
10,000-cfs Diversion. The Gauge Readings arc for 
the Entire Year, and the Entire Growing Periods of 
30 April-1 October and 10 July-1 October, 1971, 1973, 
and 1977. 



Predicted Average Predicted Average Predicted Average 

Gauge Reading Gauge Reading Gauge Reading 

with No Additional at 6,600-cfs at 10,000-cfs 

Diversion, msl (ft) Diversion, msl (ft) Diversion, msl (f 



Year 

1971 

1973 

1977 

1971 

1973 
1977 

1971 



52 Weeks (365 Days) 

433.7 435.0 

1 (1 .3)? 1 f 

I 



438.7 
\ 



432.2 



-(0.6)- 
(1.4) 



-(2.0). 

439.3 
I 



(0.7). 



433.6 
I I 



-(2.5) 



(1.1)- 
I 



30 April-1 October (155 Days) 



431 .9 
I 



(1.8)- 
I 



433.7 
/I 



437.0 
I 



-(2.9). 
438.7 



-(1.7)- 



433.4 
I 



(1.6)- 
I 



435.0 
I I 



•(2.2). 



10 July-1 October (83 Days) 



431 .9 
1 



-(1.4). 
1 



433.3 
I I 



(2.6) 



(1.1)- 
I 



(0.6) 
I 



(1.2). 
I 



435.7 
I 



434.7 



434.8 
I 



435.6 
I 



434.5 
I 



1973 
1977 



432.6 
I 



434.1 
I 



(2.4). 
-<1.4)- 



435.0 



435.5 
I I 



(2.1)- 



■(0.7). 

I 



436. 



Di ff erences 



Wildlife Introduction 



hundreds of acres of mud flats in and around each lake. 
The range of water levels between July and October determines 
the amount of mud flats that are exposed in the bottomland 
lakes, and thereby governs the vegetation and associated 
invcrtLbrate and vertebrate fauna that comprise the mud- 
flat communities. As the water levels exceed the eleva- 
tion of the tree line, bottomland forest communities 
become inundated and possibly damaged if inundation occurs 
and persists during the 30 April-1 October growing season. 
If the water levels continue to rise, water would begin to 
encroach upon unleveed and eventually leveed private and 
public property. 



4-1 



CHAPTER 4 : SURFACE AREA AND VOLUME OF BOTTOMLAND LAKES 
IN THE ILLINOIS RIVER VALLEY 



The surface areas of the bottomland lakes in the Illinois 
River valley have been estimated by a number of researchers 
[Mills et al., 1966: 5; Bcllrose et al., 197^^: C-3). We 
have compiled data for the area of the lakes presently 
occurring in the Illinois Valley from the best available 
sources. A study of the volume of selected bottomland 
lakes has also been completed. This information enabled 
us to further ascertain the effects of increased diversion 
of Lake Michigan water into the Illinois River on fish and 
wildlife habitats. Metric equivalents of the tables pre- 
sented in this chapter are included in Tables B-1 through B-7 
in Appendix B. 



METHODS 

Surface Area 

The surface area of the bottom.land lakes was determined 
from four sources. The first source was base maps of the 
Illinois River made by the Corps of Engineers in 1933. 
These maps were used sparingly because of landscape changes 
that have occurred in the valley since their completion. 
Our second source of information was the 1969 Report for 
Recreational Development by the Illinois Department of Con- 
servation and Illinois Division of Waterways. We also 
used a series of aerial photographs taken in 1974 by the 
Corps of Engineers, Chicago District. These photos were 
not rectified; therefore, the scale of the photos was de- 
termined for each individual lake examined. The fourth 
source was a map of Upper Peoria Lake made by the Corps 
of Engineers in 1976. 

The tree line was used as the boundary of the bottom- 
land lakes because annual fluctuation of water levels re- 
sults in constant variance in lake area. The only excep- 
tion was Upper Peoria Lake where normal pool elevation 
was used instead of the tree line because elevations above 
normal pool were not provided on the map made by the Corps 
of Engineers. The elevation of the tree line was resolved 
by taking from six to twelve depth measurements at the 



Wildlife Introduction 3-6 



hundreds of acres of mud flats in and around each lake. 
The range of water levels between July and October dcterinines 
the amount of mud flats that are exposed in the bottomland 
lakes, and thereby governs the vegetation and associated 
invertebrate and vertebrate fauna that comprise the mud- 
flat communities. As the water levels exceed the eleva- 
tion of the tree line, bottomland forest communities 
become inundated and possibly damaged if inundation occurs 
and persists during the 30 April-! October growing season. 
If the water levels continue to rise, water would begin to 
encroach upon unleveed and eventually leveed private and 
public property. 



4-1 



CHAPTER 4 : SURFACE AREA AND VOLUME OF BOTTOMLAND LAKES 
IN THE ILLINOIS RIVER VALLEY 



The surface areas of the bottomland lakes in the Illinois 
River valley have been estimated by a number of researchers 
(Mills et al., 1966: 5; Bellrose et al., 197:7: C-3). We 
have compiled data for the area of the lakes presently 
occurring in the Illinois Valley from the best available 
sources. A study of the volume of selected bottomland 
lakes has also been completed. This information enabled 
us to further ascertain the effects of increased diversion 
of Lake Michigan water into the Illinois River on fish and 
wildlife habitats. Metric equivalents of the tables pre- 
sented in this chapter are included in Tables B-1 through B-7 
in Appendix B. 



METHODS 

Surface Area 

The surface area of the bottomland lakes was determined 
from four sources. The first source was base maps of the 
Illinois River made by the Corps of Engineers in 1933. 
These maps were used sparingly because of landscape changes 
that have occurred in the valley since their completion. 
Our second source of information was the 1969 Report for 
Recreational Development by the Illinois Department of Con- 
servation and Illinois Division of Waterways. We also 
used a series of aerial photographs taken in 1974 by the 
Corps of Engineers, Chicago District. These photos were 
not rectified; therefore, the scale of the photos was de- 
termined for each individual lake examined. The fourth 
source was a map of Upper Peoria Lake made by the Corps 
of Engineers in 1976. 

The tree line was used as the boundary of the bottom- 
land lakes because annual fluctuation of water levels re- 
sults in constant variance in lake area. The only excep- 
tion was Upper Peoria Lake where normal pool elevation 
was used instead of the tree line because elevations above 
normal pool were not provided on the map made by the Corps 
of Engineers. The elevation of the tree line was resolved 
by taking from six to twelve depth measurements at the 



4-2! 



Area 5 Volume 



tree line during high water and averaging these readings for 
each lake sampled, A total of 18 bottomland lakes were 
selected for field determination of the mean sea level 
(msl) elevation of the tree line. From these measure- 
ments the tree lines of other bottomland lakes were 
ascertained. The area of each lake was determined by 
using a compensating polar planimeter. (Tables 4-1 - 4-5). 

Volume 

Lake depths were necessary for volume determinations. 
Because of time constraints, representative bottomland 
lakes were selected for volume analyses based on their 
size and location. Between five and twelve transects 
were established across each lake depending on its size 
and configuration. Depths were taken at intervals of 
approximately 45-91 m (50-100 yds). The depths recorded 
at each lake were adjusted to the closest river gauge 
reading to determine the bottom elevation. These transects 
with their associated depths were transcribed onto photo- 
copies of aerial photos of each lake taken by the Army 
Corps of Engineers, Chicago District in 1974. The depths 
of Upper Peoria Lake were provided by the Corps of Engineers 
on a 1976 map. Contour lines at IS-cm (6-in) intervals 
were drawn onto the photocopies and the 1976 Upper Peoria 
Lake map. The area of each contour was determined by 
using a compensating polar planimeter. The volume at each 
contour interval was calculated by multiplying surface 
area by the mean depth of each contour interval. 

The percentage of surface area and volume at each 
contour interval was determined for each of the selected 
lakes. These percentages were totaled for each pool and 
the surface area and volume extrapolated for all the water 
area in that pool (Tables 4-6 through 4-10). 

The selected lakes sampled composed a total of 17,208.9 
ha (42,523.1 surface acres) representing 60.21, of the 
surface area of the bottomland lakes in the Illinois River 
valley. Therefore, we believe .:.t the conclusions 
drawn from our sample of lakes are indicative of the 
surface area, volume, and depth of the lakes in the 
entire Illinois River valley. 

The 24 bottomland lakes sampled i.r volume analyses are 
shown in Figure 4-1 . Nine lakes wt. e studied in Peoria 
Pool, 13 in La Grange Pool, air' 2 in Alton Pool. 



Table 4-1. Surface Area of Lakes between Chicago and 
Starved Rock Lock and Dam (Upper Pools). 



4-3 



Area 

Jackson Creek Lake 

Lake 

Kankakee River Lake 

Dresden Island Dam 
Impoundment 

Total 



River M 


ile 






Hectares 


Acres 


Dresden Isl> 


and 


P 


00 


1 




278 








2.9 


7.2 


277 








12. 1 


30.0 


273 








7.8 


19.2 


272 








196.4 
219.2 


485.2 
541 .6 



Marseilles Pool 



Aux Sable Lake 


270 


30.6 


75.6 


Negro Slough 


268 


4.0 


9.8 


Peacock Slough 


265 


5.3 


13.2 


Moody Bayou 


254 


3.5 


8.6 


McNeills Bayou 


252 


12.4 


30.8 


Total 




55.8 


138.0 



Lake 

Starved Rock Dam 
Impoundment 

Total 



Starved Rock Pool 
233 
233 



45.8 
875.2 

921 .0 



113.1 
2,162.6 

2,275.7 



Grand Total for 
Upper Pools 



1 ,196.0 



2,955.3 



Table 4-2. Surface Area of 


the Lakes m 


tne feori 


a i'ooi. 


Area 


River Mile 


Hectares 


Acres 


Ponds, Utica to Spring Vail 


ey 230-214 


215.6 


532.8 


Turner Lake 


215 


140.9 


348.1 


Lyons Lake 


213 


17.6 


43.4 


De Pue Lake 5 Hick Slough 


211 


266.3 


658.0 


Spring Lake 


210 


238.2 


588.7 


Coleman Lake 


210 


52.3 


129.2 


Round Lake 


209.5 


6.1 


15.0 


Lost Lake 


209 


2.5 


6.3 


Hickory Ridge Lake 


208 


23.9 


59.0 


First Bridge Lake 


207 


5.9 


14.6 


Goose Lake 


204 


823.2 


2,034.1 


Senachwine Lake 


201 


1,653.7 


4,086.3 


Siebolts Lake 


200 


177.4 


438.4 


Sawmill Lake 


197 


282.4 


697.7 


Mud Lake 


196 


26.4 


65.3 


Town Lake 


195 


26.9 


66.5 


Whitney Lake 


195 


6.6 


16.3 


Meridian Slough 


194 


19.3 


47.7 


Billsbach Lake 


194 


438.2 


1,082.8 


Weis Lake 


192 


132.9 


328.4 


Fisher's Slough 


191 


147.0 


36 3.2 


Sparland (Goose) Lake 


190 


432.0 


1 ,067.6 


Wightman Lake 


188 


258.2 


638.0 


Sawyer Slough 


188 


199.9 


494.1 


Babbs Slough 


185 


791.5 


1,955.7 


Big Meadow Lake 


184 


274.6 


678.6 


Upper Partridge DLD 


181 


635.5 


1,570.2 


Lower Partridge DLD 


180 


277.2 


684.9 


Goose Pond 


178 


832.4 


2,056.8 


Upper Peoria Lake 


172 


3,738.9 


9,238.7 


Lower Peoria Lake 


164 


1,044.7 


2,581.5 


Beesaw Lake 


158 


77.0 


190.3 


Wesley Slough 


160 


30.7 


76.0 



Total 



13,295.9 32,854.2 



Table 4-2. Surface Area of the Lakes in the Peoria Pool. 



4-4 



Area 


River Mile 


Hectares 


Acres 




Ponds, Utica to Spring Vail 


ey 230-274 




215.6 


532 


.8 


Turner Lake 


215 




140.9 


348 


. 1 


Lyons Lake 


213 




17.6 


43 


.4 


De Pue Lake 5 Hick Slough 


211 




266.3 


658 


.0 


Spring Lake 


210 




238.2 


588 


.7 


Coleman Lake 


210 




52.3 


129, 


. 2 


Round Lake 


209.5 




6. 1 


15, 


.0 


Lost Lake 


209 




2.5 


6. 


,3 


Hickory Ridge Lake 


208 




23.9 


59. 


.0 


First Bridge Lake 


207 




5.9 


14, 


.6 


Goose Lake 


204 




823.2 


2,034, 


. 1 


Senachu'ine Lake 


201 


1 


,653.7 


4,086, 


. 3 


Siebolts Lake 


200 




177.4 


438. 


.4 


Sawmill Lake 


197 




282.4 


697. 


, 7 


Mud Lake 


196 




26.4 


65, 


.3 


Town Lake 


195 




26.9 


66, 


.5 


Whitney Lake 


195 




6.6 


16, 


.3 


Meridian Slough 


194 




19.3 


47, 


.7 


Billsbach Lake 


194 




438.2 


1 ,082, 


.8 


Weis Lake 


192 




132.9 


328, 


,4 


Fisher's Slough 


191 




147.0 


365. 


,2 


Sparland (Goose) Lake 


190 




432.0 


1 ,067. 


,6 


IVightman Lake 


188 




258.2 


638. 


.0 


Sawyer Slough 


188 




199.9 


494. 


, 1 


Babbs Slough 


185 




791 .5 


1 ,955. 


,7 


Big Meadow Lake 


184 




274.6 


678. 


.6 


Upper Partridge DLD 


181 




635.5 


1 ,570. 


,2 


Lower Partridge PLD 


180 




277.2 


684. 


,9 


Goose Pond 


178 




832.4 


2,056. 


,8 


Upper Peoria Lake 


172 


3 


,738.9 


9,238. 


,7 


Lower Peoria Lake 


164 


^ , 


,044.7 


2,581 . 


5 


Beesaw Lake 


158 




77.0 


190. 


, 3 


Wesley Slough 


160 




30.7 


76. 


,0 


Total 




13, 


,295.9 


3 2,854. 


,2 



Table 4-3. Surface Area of the Lakes in the La Grange Pool, 



Area 



Larish Lake 
Long 5 Mud Lakes 
Pekin 5 Worley Lakes 
Wood Duck Slough 
Boot Jack Lake 
Kingston Lake 
Ferry Lake 
Spring Lake 
Pond Lily Lake 
Rice-Miserable Lake 
Beebe (Big) Lake 
Lost Lake 
Goose Lake 
Clear Lake 
Lake Chautauqua 
Liverpool Lake 
Quiver Lake 
Horseshoe Lake 
Matanzas Lake 
Dierker Lake 
Bath Lake 
Moscow Bay 
Grass and Bell Lakes 
Carlock (Swan) Lake 
Jack Lake 
Anderson Lake 
Patterson Bay 
Curtis Lake 
Powell Bay 
Mathews Bav 



River . . 1 


5 Hectares 


Acres 


157 


7.0 


17.2 


156 


190.9 


47,1.6 


155 


290.2 


717.2 


149 


3.0 


7.5 


148 


102.8 


254.0 


147 


30.9 


76.4 


144 


6.5 


16.1 


137 


520.0 


1 ,285.0 


136 


27.8 


68.7 


136 


611.2 


1,510.3" 


136 


552.7 


1,365.8 


135 


15.7 


38.9 


134 


333.1 


823.0 


132 


781 .5 


1,931 .0 


128 


1,522.8 


3,762.8 


128 


74.7 


184.6 


123 


112.2 


277.2 


121 


9.5 


23.4 


116 


193.9 


475.2 


114 


3.2 


7.8 


113 


59.6 


147.3 


109 


107.8 


266.5 


111 


232.7 


575.1 


110 


117.0 


289.2 


108 


361 .7 


893,7 


110 


665.8 


1,645.1 


107 


57.7 


142.'' 


107 


7.0 


17.2 


106 


2? 4 


62.8 


106 


15.6 


58. D 



Sheet 1 of 2 



4-7 



Table 4-4. Surface Area of the Lakes in the Alton Pool from 
La Grange to Grafton, Illinois. 



Area 

Meredosia Lake 

Ponds; Meredosia Island 

Barlow Lake 

Smith-Atkinson Area 

Aliens Lake Area 

Jack Ellis Lake 

Prairie Lake 

Hurricane Island Slough 

Godars Swamp 

Diamond Island Slough 

Hamilton Lake 

Hemboldt Slough 

The Glades 

Fowler Lake 

Deep Lake 

Long Lake 

Upper 5 Lower Flat Lake 

Stump Lake 

Swan and Fuller Lakes 

Gilbert Lake 

Calhoun Point 



River Mile Hectares Acres 



75 


600.6 


1 ,484.0 


74 


76.9 


190.1 


68 


20.0 


49.4 


67 


120.3 


297.2 


63 


77.7 


192.0 


57 


7.7 


19. 1 


56 


8.9 


22.0 


27 


4.9 


12.0 


26 


55.0 


136.0 


24 


51 .2 


126.5 


23 


4.9 


12.0 


14 


19.4 


48.0 


14 


103.6 


256.0 


12 


97.1 


240.0 


11 


17.8 


44.0 


11 


27.5 


68.0 


10 


64.7 


160.0 


9 


223.4 


552.0 


8 


1 ,162.6 


2,872.7 


5 


93.9 


2 3 2.0 


3 


351 .4 


86 8.3 



Total 



3,189.5 7,881.3 



Table 4-5. Total Surface Area of -he Lakes in the Entire 
Illinois River Valley from Chicago to Grafton, 



Pool 

Upper Pools 
Peoria Pool 
La Grange Pool 
Alton Pool 



Hectares 

1,196.0 
13,295.9 
10,918.6 

3,189.5 



Acres 

2,955.3 
32,854.2 
26,979.9 

7,881 .3 



Total 



28,600.0 



70,670.7 



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Table 4-7. Surface Area (Acres) and Volume (Acre-Feet) of I 
Upper Peoria Lake (Peoria Pool) based on 0.5- ! 
and 1.0-ft Contour Intervals below Normal \ 
Tool Elevation. ; 



Water 

msl 


Depth 
feet 

0.0 


Surf, 
A^ 


ace -■ rea , 
cres 


, Volume, 
Acre-Feet 

elevation 


% of 
Total 
Acres 


% of 
Total 
Acre-Feet 


440.0 


normal pool 




459.5 


0.5 




191.9 


48.0 


1.82 


0.15 


439.0 


1.0 




237.7 


178.3 


2.25 


0.56 


438.5 


1 .5 




342.8 


428.5 


3.24 


1 .34 


438.0 


2.0 




463.3 


810.8 


4.39 


2.54 


437.5 


2.5 


1 


,713.5 


3,855.4 


16.22 


12.07 


437.0 


3.0 


1 


,474.1 


4,053.8 


13.95 


12.69 


436.5 


3.5 


2 


,112.9 


6,866.9 


20.00 


21 .50 


436.0 


4.0 


1 


,349.7 


5,061 .4 


12.77 


15. S4 


435.5 


4.5 




969.0 


4,118.3 


9.17 


12.89 


435.0 


5.0 




364.1 


1,729.5 


3.45 


5.41 


434.0 


6.0 




476.9 


2,623.0 


4.51 


8.21 


433.0 


7.0 




132.8 


863.2 


1.26 


2.70 


432.0 


8.0 




78.6 


589.5 


0.74 


1.85 


431.0 


9.0 




84.7 


720.0 


0.80 


2.25 


Channel 


^ 9. 




573.8 




5.43 




Total 




9, 


,992.0 


31,946.6 


100.00 


100.00 



Total + Channel 10,565.8 
Ave. Depth, ft^ 3.20 



Gauge reading in Mean Sea Level at Peoria, Illinois 

^Channel not included in total volume. 
Acre-ft T acres. 



4-13 





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4-19 




16 - 1NG«^'' 

17 - STEUAin 
IB - CHAIN 

19 • CRANE 

20 - BERtOOSIA 

21 - SUAN 



Figure 4-1. Bottomland lakes along the Illinois River selected 
for depth transects. 



Area 5 Volume 



Discrepancies between the surface area of the bottomland 
lakes (Tables 4-2 -4-4 j and the surface area on which volu- 
metric work was based (Tables 4-7 through 4-9) 
result from difficulties in obtaining the depths of certain 
portions of lakes because of physi' rl obstructions such as 
levees. Upper Peoria, Goose (Liverpool), Ingram, Stewart, 
Chain and Swan lakes all had portions of their basins 
that were inaccessible because of levees. The area of the 
lakes on Grand Island differs because a small lake 
separated from the Grass-Carlock- Jack chain of lakes 
could not be sampled. 

Average Depth 

The average depth of the lakes sampled, the four 
pools, and all the bottomland lakes was derived by dividing 
the volume of the region desired by its surface area (i.e., 
acre-feet i acres = average depth). 



Mud Flat Area and Percent Occurrence of Water Levels 

Mud flats occur in the area exposed between the tree 
line and low water levels. Maximur exposure of mud flats 
occurs at traditional low water periods, primarily in 
July, August, and September (Figure 4-2 ). The area of 
mud flats exposed varies with water levels. Tables 4-11 
and 4-12 illustrate the amount of area exposed at 15-cm 
(6-in) intervals starting from the tree line for Peoria 
and La Grange pools. 

Except where portions are leveed, bottomland lakes 
in the Peoria Pool are directly ccimecteJ v.ith the 
Illinois River. Therefore, water levels that occur in the 
river directly affect the bottomland lakes. in La 
Grange and Alton pools, the majority of bottomland lakes 
are separated from the river by natural and/or man-made 
levees. As a result, water levels in the bottomland lakes 
in these pools may differ somewhat from water levels in 
the river. 

The determination of surface area, mud flat area, and 
voluir,. .-.-plicated where bottomland lakes have water 
levels independent of that of the river. This factor is 
partially negated, however, by the management for moist- 
soil plant production ir. many of the bottomland lakes in 
La Grange and Alton pools. Water aewds in the«;e manaeed 
lakes are maintained by gravity flow and are similar to 



4-21 



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VNVAVH IV Cl*'"^ 13A31 ii3LVf\ 



4-22 



Table 4-11. The Number of Acres of Mud Flats Exposed in 

Certain Lakes of the Peoria Pool in Relation to 
Mean Sea Level River Stages at Henry for the 
Entire Growing Season of 10 July-1 October, 
1939-1978. 







MSL Hen 


iry, 


, Feet 








442.1+ 


441.6 




441 .0 


440.5 


Total 


Lake De Pue 








94.4 


87.2 


181.6 


Goose Lake 








444.3 


459.1 


903.4 


Senachwine 
Lake 


G 

•H 






422.9 


210.3 


633.? 


Sawmill Lake 

Billsbach 
Lake 

Sparland 
Lake 


(D 
4-> 

> 
O 


0) 

c 

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1-1 

o; 
a> 

4-> 




171 .9 
164.1 

261.9 


56.7 
116.1 

111.0 


228.6 
280.2 

372.9 


Babbs Slough 








583.2 


239.8 


823.0 


Total Acres 






2, 


,142.7 


1,280.2 


3,422.9 


Expanded 
Acres for 
Peoria 
Pool a 






3, 


,619.1 


2,323.8 


5,942.9 



Occurrence^ ^2.5 15.0 25.0 47.5 

Selected lake conditions expanded for entire pool area on 
basis of seasonal stages by years (Table 4-10). 

Percent of years from 1939-19:" tv^t water levels for the 
period 10 July-1 October averaged this heignt. 



4-23 



Table 4-12. The Number of Acres of Mud Flats exposed in 

Certain Lakes of the La Grange Pool in relation 
to Mean Sea Level River Stages at Havana for 
the Entire Growing Season of 10 July-1 October, 
1939- 1978. 



msl 

Havana, Goose Beebe F<ice Clear Lake 

ft Lake Lake Lake Lake Chautauqua 



434.9+ above tree line 



434.4 tree line 



433.9 116.2 



2 4 3.4 



208.5 



253.6 502.4 



433.4 44.0 



167.8 



51 .9 



130.4 492.8 



432.9 67.5 



293.5 



69.0 154.0 525.3 



432.4 135.5 366.5 



242.7 1,246.4 



431.9 119.5 



273.9 



123.5 247.7 



;37.2 



431 .4 
430.9 
430.4 



16.7 



3.3 



353.1 416.6 



478.0 



0.7 138.0 



349. 1 



136.9 



158.7 



Total 482.7 1,365.8 1,510.3 1,931.0 3,762.8 



Sheet 1 of 3 



Table 4-12 continued -- La Grange Pool Lalc^s' Mud Flats 



msl 

Havana, Anderson 

ft Lake 



Grand 
I si and 



Ingram- 
Stewart 

l.nkes 



Chain 
Lake 



434.9+ above tree line 



434.4 tree line 



433.9 


193.2 


343.2 


433.4 


106.8 


146.8 


432.9 


99.2 


123.1 


432.4 


141.3 


520.0 


431.9 


212.9 


409.2 


431.4 


246.6 


59.3 


430.9 


303.3 


93.0 


430.4 


335.3 


21.5 



354.9 



340.6 



415.7 



505.9 



60.4 



49.0 101.9 



39.0 146. 



347.9 149.9 



153.9 



192.6 107.1 



215. 



93. 



Total 



1,638.6 1,716.1 2,157.6 559.3 791.7 



Sheec 2 uf 7 



4-25 



Table 4-12 concluded -- La Grange Pool Lakes' Mud Flats 



msl 




Havana, 


Total 


ft 


Acres 



434.9+ above tree line 



434.4 tree line 



433.9 
433.4 
432.9 
432.4 
431 .9 
431 .4 
430.9 
430.4 

Total 



2,359.5 
1 ,632.0 
1,932.3 
3,453.5 
2,977.5 
1 ,619.3 
1 ,290.1 
651 .7 

15,915.9 



Expanded 

Acres , 
La Grange 

Pool ' 



3,998.4 
2,765.4 
3,272.7 
5,851 .9 
5,045.2 
2,743.9 
2,185.4 
1 ,103.5 

26,966.4 



Yearly 
Occurrence ' 

5.0 

2.5 

0.0 

7.5 
10.0 

7.5 
15.0 
15.0 
17.5 
20.0 

100.0 



Selected lake conditions expanded for entire pool area on 
basis of seasonal stage by years (Table 4-10). 

Percent of years between 1939-1978 that water levels for 
the period 10 July-1 October averaged this height. 



Sheet 5 of 3 



Area 5 Volume 






river levels in order to maximize the mud flat area p-'-^ilcble 
for colonization by moist-soil plants. Some bnttOi'..A^,id 
lakes have low natural levees or man-T^' \ levees that are 
in disrepair. Hence, we believe that estimates of surface 
area and volume, although not adjusted for each individual 
lake, are sufficient for comparative purposes. 

The percent occurrence of water levels for the 
10 July-1 October growing period (the optimum time of 
mud flat exposure for moist-soil plant development) was 
calculated by determining the mean water level during 
this period for each of the 40 years from 1939-1978. The 
percent occurrence of these average water levels for each 
growing season was calculated for the 40 years (Tables 4-11 
and 4-12) . 



RESULTS 



A total of 28,600.0 hectares (70,670.7 acres) of 
bottomland lakes presently occur in the Illinois River 
valley (Table 4-5 ). Of the designated pools of the 
Illinois River valley, Peoria Pool has the largest amount 
of area in bottomland lakes mainly because of Peoria 
Lake, a large mainstem lake. La Grange and Peoria pools 
combined contain 84.71> of the total area in bottomland 
lakes. The Upper Pools have few bottomland areas as a result 
of the narrow river valley in this portion of the valley 
and a greater rate of fall in the river above Starved 
Rock. Alton Pool also has few bottomland lakes; this results 
from the elimination of numerous bottomland lakes by the 
drainage and leveeing of a large proportion of the flood- 
plain for agricultural purposes. 

Tables 4-6 through 4-10 illustrate the volume 
and average depth present in the bottomland lakes of 
the Illinois River valley. The most striking and despairing 
finding is that the average depth of bottomland lakes 
in the Illinois Valley is currently only 0,62 m (2.04 ft). 

The parameters affecting the different navigation 
pools are similar but vary with geographic and hydrologic 
factors. Although mentation has adversely affected 
all of the bottc .x^^., lakes, ^differences between pools do 
occur. The laLes in Peoria Pool ait gcr.c-^-ily directly 
connected to the river, but many of the bottomiarJ ikes 
in La Grange Pool are at least partially protected by 
levees. Mud flats are more prevalent in La Grange Pool 



Area 5 Volume 



4-27 



than in Peoria Pool. Based on elevation alone, 99b of the 
lake basin area in La Grange Pool would not contain water 
except where retained by natural banks or levees during 
4ow water. In Peoria Pool, only 28.36 of the lake basin 
area would be exposed during low water. The reason for 
this discrepancy is that Peoria dam is one foot higher 
than La Grange dam and the rate of fall is lower in Peoria 
Pool. Therefore, water levels vary less in Peoria Pool. 



Although most of 
one another, there are 
lake that we sampled i 
has a tributary stream 
ting the serious sedim 
main stem of the river 
deeper and has remaine 
lakes because the chan 
taining a current that 
La Grange Pool, three 
Anderson, and Crane, 
relatively deep as a r 
river and levees. And 
tively deep because le 
tion by small and mode 



the bottomland lak 

some differences. 

n the valley (Goos 

that flows into i 

entation problem a 

Peoria Lake was 

d deeper than the 

nel flows through 

keeps sediment su 
of the deepest lak 
Rice and Crane lak 
esult of their dis 
erson Lake has als 
vees have protecte 
rate floods of the 



es closely resemble 

The most -shallow 
e Lake, Peoria Pool) 
t, thus aggrava- 
rising from the 

historical ly 
other bottomland 
it thereby main- 
spended. In 
es are Rice, 
es have remained 
tance from the 
o remained rela- 
d it from inunda- 

river . 



EFFECTS OF DIVERSION 



Surface Area 

An increase in diversion of Lake Michigan water will 
raise water levels in the Illinois River and, therefore, 
enlarge the surface area of bottomland lakes. This pro- 
posed increased diversion is scheduled mainly during low 
water periods that customarily occur in July, August, 
and September (Figure 4-2 and Table 3-1 ). By com- 
paring the predicted increased water levels during the 
10 July-1 October period (Table 3-1 ) with the graduated 
surface area of bottomland lakes (Table 4-10 ), the 
amount of altered surface area can be ascertained. 

The predicted increased water levels have been 
determined from the U.S. Army Corps of Engineers' computer 
model for the Henry and Havana gauges. These gauging 
stations are located midway in the Peoria and La Grange 
pools and, thus, are indicative of conditions in their 
respective pools. The computer model was completed for 
three years, 1971, 1973, and 1977, that were dissimilar 
in terms of water levels. Because of the variation in 



4-2 
Area § Volume 



water levels during each of the three year=^. we averaged 
the increase in water levels for all three years involved. 
The average increase for all three years for the 6,600-cfs 
diversion at both Henry and Havana was 0.52 m (1.7 ft). 
In 1973, high water levels precluded any hypothetical 
10,000-cfs diversion. The average of both 1971 and 1977 
for the 10,000-cfs diversion at Henry was 0.85 m (2.8 ft) 
and the average at Havana was 0.73 m (2.4 ft) (Table 3-1). 

By adding the increase in water levels resulting 
from diversion to the low water levels at Henry and 
Havana (440.5 and 430.4 ft C"isl3, respectively), the 
amount of area enlarged over low water levels could be 
computed. In the Peoria Pool, the 6,600- and 10,000-cfs 
diversion would enlarge the water area of ^ ottomland 
lakes by at least 2,406.0 ha (5,942.9 acre^j during late 
summer and early fall. In addition, an unknown amount 
of bottomland timber would also be inundated. In the 
La Grange Pool, the 6,600- and 10,000-cfs diversion would 
increase the acreage of water surface by approximately 
4,038.3 and 7,732.4 hectares (9,974.5 and 19,099.1 acres), 
respectively. The increased water area in the La Grange 
Pool is a maximum figure because a significant number of 
areas are buffered from changes in water levels by levees. 



Mud Flats 

Increased diversion would result in the enlargement 
of bottomland lakes during late summer and early fall by 
submerging areas of the lake basin that would normally 
form mud flats. Therefore, under either the proposed 
6,600- or 10,000-cfs diversion schedules, 2,406.0 ha 
(5,942.9 acres) of mud flats (1001) would be lost in 
Peoria Pool because of the shape of its bottom (Table 4-11) 
In the La Grange Pool, 4,038.." - (9,974.5 acres) of mud 
flats (approximately 401) would be inundated by the 
6,600-cfs diversion rate and 7,732.4 ha (19,099.1 acres) 
(approximately 75'<.) would be lost with the 10,000-cfs 
diversion scheme (Table 4-12 ). These figures refer to 
the reduction of mud flats during low water, which occurs 
47.5*0 of the time in Peoria Pool and 20. Oi in La Grange 
Pool (Tables 4-11 5 4-12 ). The area of mud flats ex- 
posed varies from year to year as summer water levels 
change. 



4-29 
Area 5 Volume 

Volume 

The increased water levels resulting from additional 
diversion would affect the volume of the bottomland lakes 
as well as the area. In Peoria Pool, the 6,600- or 10,000- 
cfs diversion would increase the volume of bottomland lakes 
at low water by at least 2,647.7 acre-feet (Tatle 4-10). The 
water level would be raised above the tree line. Unfor- 
tunately, elevations above the tree line were not available. 
Therefore, although substantial increases in volume would 
occur, the magnitude of these increase? cannot be estimated. 
In La Grange Pool, a diversion of 6,600 cfs would in- 
crease the volume by 26,000 acre-feet and a 10,000-cfs 
diversion would increase the volume by 40,331.7 acre-feet 
(Table 4-10) . 

Compar i sons 

The proposed increased diversion would have the least 
impact upon the Upper Pools of the Illinois River valley. 
As a result of the greater rate of fall and lack of bottom- 
land areas, the Upper Pools would change relatively little. 
Conversely, Peoria Pool would be greatly affected by 
increased diversion because most of the bottomland lakes 
are directly connected with the river. Therefore, any 
fluctuations in river levels would immediately affect 
the area and volume of associated bottomland lakes. In 
the La Grange and Alton pools, natural and man-made levees 
buffer some of the changes in river levels from bottom- 
land areas. Hence, although changes in surface area and 
volume would occur, the effect of increased diversion on 
bottomland areas in these pools may be less than in 
Peoria Pool. 



Average Depth 

The average depth of the bottomland lakes would in- 
crease proportionately with increases in water levels re- 
sulting from diversion. Therefore, in Peoria Pool a 
6,600-cfs diversion would increase the average depth of the 
bottomland lakes at low water by 0.52 m (1.7 ft) 
Table 4-10 ). The 10,000-cfs diversion would increase 
the average depth bv 0.85 m (2.8 ft). Similarly in La 
Grange Pool, the 6,'600-cfs diversion -vould increase 
average depths of bottomland lakes at low water by 0.52 m 
(1.7 ft} and a 3n,000-c£s diversion by 0.74 m (2.4 ft) 
(Table 4-10) . 



4- 



Area 5 Volume 



We believe that increased diversion would increase 
the rate of sedimentation in the bottomland lakes by 
increasing water levels. Although the Lake Michigan 
water diverted into the Illinois River would be rela- 
tively sediment-free, the increased water levels during 
traditional low water periods would not permit sediment- 
laden water to escape from the bottomland lakes. The 
higher water column would allow more sediment to settle 
in the bottomland lakes thereby increasing the rate of 
fill. If diversion was then discontinued, the average 
depth would be less than if no diversion were initiated. 



5-1 



CHAPTER 5 : VEGETATION 



BOTTOMLAND FOREST 



Before colonization by the white man, the maiority of 
the bottomlands along the Illinois River were forested. 
Today, however, much of the bottomland forests in the river 
valley have been converted to agricultural fields. According 
to Emge et al. (1974: 101), the amount of the Illinois River 
valley presently covered by forest is approximately less 
than 15°6 above La Salle; from 15 to 50% between Spring Valley 
and Henry; less than ISs between Henry and Havana; from 15 to 
30S between Havana and Kampsville; and from 30 to 50^ 
between Kampsville and Grafton. 

The woodland vegetation associated with the Illinois 
River can be separated into four categories from the water's 
edge to upper limits of the floodplain: (1) the black 
willow-cottonwood community, (2) the silver maple (softwoods) 
community, (3) a mixed community, and (4) an upland or oak- 
hickory community. The boundaries of these communities and 
their associated species distribution are delineated by oxygen- 
water relationships governed by soil texture and flooding. 
Most of the bottomland soils are of recent glacial origin, 
but show no profile development because of the annual re- 
currence of floods. 



Black Wi 1 low-Cottonwood Community 

Near the water's edge, seedlings of the black willow 
( Salix nigra ) and cottonwood ( Populus del toides ) develop. 
Black willows and cottonwoods are pioneer species that soon 
take over new mud bars, points, and shorelines. Willows 
and cottonwoods are found in abundance only on open areas 
exposed to direct sunlight and nearly devoid of litter and 
ground cover. These conditions can be found on newly 
formed land areas consisting of soils with low moisture- 
holding capabilities. Cottonwood seedlings appear in dense 
stands on well-drained soil and willows in the low moist 
areas (Yeager, 1949: 45). 



m 



Vegetation 

Belts of willows usually occur along the water's edge, 
each belt increasing in age and height as the distance froir 
the water's edge increases. Willows are important because 
as they invade new areas, they also create new areas by 
slowing the flow of high water thus accelerating the deposi- 
tion of sediment. Willow seedlings can survive inundation 
longer than cottonwoods (Hosner and Minckler, 1963: 38), one 
reason being that willow seedlings are initially faster- 
growing than concurrently established cottonwood seedlings. 
Thus, willow seedlings are less apt to be completely sub- 
merged during periods of high water resulting in better 
survival than cottonwood seedlings. However, because cot- 
tonwoods tend to form a deeper root system than willows, 
any drop in the water table tends to favor greater survival 
of cottonwoods (Barclay, 1924: 91). 

Young willow stands are often so dense that other tree 
species are excluded. However, both willows and cottonwoods 
are shade- intolerant and eventually are joined or invaded 
by shade- tolerant species such as silver maple ( Acer saccharin 
Soil-water relationships also govern changes in species 
distribution. Other species that occur in this community, 
especially along the southern reaches of the river, are 
such water- tolerant woody vegetation as swamp privet 
( Forestiera acuminata ) , water locust ( Gledi tsia aquatica ) , 
swamp holly ( Ilex decidua ) , and buttonbush ( Cephalanthus 
occidentalis ) . Decreased light intensity, improved soil 
nutrition, and a change in water supply occur as the species 
change. The seedlings that develop in the cottonwood-willow 
association are mainly silver maple, elm, hackberry, box 
elder, and ash (Hosner and Minckler, 1960: 69), the primary 
species in the next community of bottomland forest. 

Mixed Softwoods 

The second community in the bottomland forest is the 
mixed softwoods. This is the most extensive forest community 
along the Illinois River. This community usually occurs 
behind the wi llow-cottonwood association, but can also 
border directly on the river. It is best developed on the 
unprotected floodplain where soils vary from sandy to silty. 
This community can withstand limited annual flooding, though 
it is less flood-tolerant than the wi llow-cottonwood commu- 
nity . 

Silver maple dominates this community. Other common 
species associated with silver maple, depending upon slight 
elevational differences, are American elm (Ulmus americana) , 



5-3 
Vegetation 

willows, cottonwoods, swamp privet, red mulberry ( Morus 
rubra ) , pecan ( Carya ill inoensis ) , box elder ( Acer negundo ) , 
green ash ( Fraxinus pennsylvanica ) , honey locust (G. tri - 
acanthos ) , river birch ( Betula nigra ) , hawthorn ( Crataegus 
spp.), sycamore ( Platanus occidentalis ) , hackberry ( Celtis 
occidentalis ) , and water locust (Yeager, 1949: 37; Klein et 
al., 1975: 38). This association is progressing toward a 
silver maple-box elder-American elm stage with willows and 
cottonwoods becoming less important. The mixed softwoods 
community appears to be a rather stable association that re- 
produces to about the same species (Hosner and Minckler, 1965: 
39). However, oak species may appear in older stands. 

Some seedlings such as sycamore, silver maple, and box 
elder appear at approximately the same time as cottonwood 
and willow seedlings in the previous community after organic 
matter begins to accumulate (Hosner and Minckler, 1963: 38). 
These species grow slower than cottonwood and willow. There- 
fore, as willow and cottonwood approach biological maturity, 
the sycamore, silver maple, and box elder are often estab- 
lished. These species can survive under the shade of 
cottonwoods and willows. 

Hosner and Minckler (1960: 76) found that American elm, 
box elder, green ash, and silver maple were the most common 
species that reproduced on bottomlands in the mixed soft- 
woods community. However, besides competition and shading, 
reproduction of some species is rather closely related to 
the available moisture-holding capacity of the subsoil. 

Mixed Community 

In the floodplains of the Illinois River on slightly 
higher elevations where flooding is less frequent, hardwood 
species become more abundant. Tree species that occur in 
this zone are pin oak ( Quercus palustris ) , silver maple, pecan, 
box elder, sugarberry (C. laevigata ) , green ash, American elm, 
and mulberry (Klein et al., 1975: 43). Other species present 
are hackberry, hawthorn, honey locust, bur oak (^. macrocarpa ) , 
persimmon ( Diospyros virginiana ) , and dogwood ( Cornus spp.). 
Neither cottonwood nor willow are very common. Some of 
the same species can occur in both the mixed softwoods and 
the mixed community. 

Yeager (1949: 39) reported that at the mouth of the 
Illinois River, pin oak, persimmon, cottonwood, and several 
less important species occurred on the highest land flooded. 
He found box elder, red mulberry, redbud, dogwood, honey 



5- 

Vegetat ion 



locust, and Kentucky coffee tree ( Gymnocladus dioicus ) on 
unflooded land, particularly on the higher ridges . 



I 



The major portion of reproduction in this type of { 

community consists of elm, hackberry, box elder, silver | 

maple, ash, and oaks (Hosner and Minckler, 1960: 70). { 

Seedlings of cottonwoods, willow, and sycamore tend to be ] 

scarce. Reproduction of cottonwoods and willows is best | 

on soils that have low moisture-holding capacity. However, j 

species found in this community type, such as pecans and ■ 

oaks, have more reproduction on heavier soils with high i 

moisture-holding capacities (Hosner and Minckler, 1960: 76). | 

It appears that as surface drainage conditions improve, | 

the mixed community group consisting of pin oak, honey I 
locust, and bur oak can reproduce and survive (Hosner and 

Minckler, 1963: 39). Following further improvement in i 

surface drainage, American elm may be a major species in I 

the overstory composition. American elm is the most common { 

understory species in the mixed community (Hosner and ; 
Minckler, 1963: 39). ■ j 

I 

Succession beyond the mixed community on bottomland j 

sites may be slow (Hosner and Minckler, 1963: 40), and this [ 

community can maintain itself as a sub-climax forest. Pro- j 

gression to an oak-hickory climax depends upon major changes ! 

in soil and soil moisture conditions, such as aggradation i 

from flood waters, changes in stream patterns, or changes ' 

in the water table level (Hosner and Minckler, 1963: 40). i 

j 
Uplands or Oak-Hickory Community ' 

The oak-hickory community is distributed in the uplands 
bordering the Illinois River where flooding does not occur. 
The most common species are white (g. alba ) , black (^. 
veluntina ) , and northern red oaks (Q. rubra ) , shagbark 
hickory ( Carya ovata) , sugar maple (A. saccharum ) , white 
ash (F. americana ), red maple (A. rubrum ) , and black walnut 
( Juglans nigra ) .~ Other species present include red mulberry 
and yellow chestnut oak (chinquapin) (Q. muhlenbergii) 
(Turner, 1936: 699). — 

Klein et al. (1975: 45) found the oak-hickory commu- 
nities along the lower Illinois River to include shellbark 
hickory (C. laciniosa ) and shagbark hickory. They also found 
oaks, in order of importance, to include shingle (Q. imbri - 
caria ) , swamp white (g. bicolor ) , pin, post (g. stellata ) , 
northern red, and chinquapin. They found the less important 



5-5 



Vegetation 



species to be red elm, hawthorn, deciduous holly, black 
walnut, pawpaw ( Asimina tri loba ) , and American basswood 
( Ti lia americanaJ T Klein et al. (1975: 45) found the trees 
that occurred only on the terraces were northern red oak, 
shingle oak, black cherry ( Prunus serotina ) , black walnut, 
chinquapin oak, and post oak. 

Turner (1936: 705) found the following additional 
species may occur on the steep slopes between the floodplain 
terraces and the bluffs: American elm, Ohio buckeye 
( Aesculus glabra ) , butternut ( Juglans cinerea ) , hackberry, 
black locust ( Robinia pseudoacacia ) , and bitternut hickory 
(C . cordiformis) . 



Islands 



The vegetation on the islands in the Illinois River 
is water- tolerant and varies between large and small 
islands. Turner (1936: 721) and Klein et al. (1975: 66) 
describe the vegetation found on Illinois River islands. 
Small islands are characterized by a pioneer type of vege- 
tation whereas larger islands support a more advanced 
stage in succession. 



Small Islands 

Small islands ar 
rounded upper end and 
or oldest end of an i 
is building up. Ther 
occurs on the lower t 
of islands. The pione 
sprouts and seedlings 
next zone is a mixtur 
sprouts, and possibly 
lows decreases in the 
more important and yo 
in the fourth zone, c 
maples are prevalent, 
fifth zone is rclativ 
dominate with cottonw 



e irregularly oval in 
a tapered downstream 
si and wears away while 
efore, the pioneer sta 
ip and also along the 
er vegetation consists 
and various herbaceou 
e of young willows, a 
swamp privet. The pe 
third zone while cott 
ung silver maples appe 
ottonwoods peak in abu 

and willows decrease 
ely stable; silver map 
oods and occasional sy 



shape with a 
end. The upper 

the lower end 
ge of plants 
outermost fringe 

of 'wi 1 low 
s plants . The 
few Cottonwood 
rcentage of wil- 
onwoods become 
ar. Elms occur 
ndance, silver 
noticeably. The 
les and elms 
camores . 



Large Islands 

The lower end of large islands has a zonation similar 

to that of small islands. However, the upper end of large 

islands has a more stable habitat and a greater number of 

plant species occur than in this region of the smaller islands 



Vegetation 



The climax island forest is not as highly developed as the 
climax forest on the mainland, probably because the islands 
are often 1 to 3 feet lower than the shoreline floodplain. 
Elm and silver maple dominate and pecan, swamp privet, pin 
oak, Cottonwood, red mulberry, sugarberry, and hackberry are 
also prevalent. Cottonwood, honey locust, and sycamore 
often attain a much higher dominance on large islands than 
on the mainland whereas hackberry, ash, hawthorn, river 
birch, swamp privet, and persimmon appear to occur in 
greater numbers in the climax floodplain forest. 



Bottomland Forest-Water Relationships 



The su 
depends upo 
duration of 
depth, the 
the amount 
Bell (1974: 
increase wi 
the frequen 
is a natura 
of flooding 
the flood z 
of low oxyg 
rooting zon 
He notes th 
determinant 
environment 
bution of a 
indicate th 
stage of de 
mature indi 
tolerance d 



rviv 
n su 

flo 
size 
of s 

44) 
th e 
cy 
1 ar 

sev 
one 
en a 
e du 
at i 

in 
. H 

spe 
e sp 
velo 
vidu 
urin 



al of woody 
ch factors a 
oding, the f 

(age) of th 
ediment, and 

writes that 
levation and 
f flooding, 
rangement of 
erity becaus 
along the gr 
nd high carb 
ring flood a 
n the lower 
the distribu 
owever, Bell 
cies along a 
ecies' toler 
pment and th 
als of a spe 
g early stag 



spec 

s th 

requ 

e sp 

the 

spe 

the 

Bel 

spe 

e th 

adie 

on d 

nd s 

reac 

tion 

(pa 

flo 

ance 

at t 

cies 

es o 



les 
e sp 
ency 
ecim 

vel 
cies 

cor 

1 (1 
cies 
e sp 
nt a 
ioxi 
atur 
hes 

of 
. 45 
odin 

dur 
he f 

may 
f de 



sub j ected 
ecies, th 

of flood 
ens, soil 
ocity of 

richness 
respondin 
974: 44) 

on a ver 
ecies are 
ccording 
de condit 
ated soil 
of the gr 
species i 
) states 
g- frequen 
ing the s 
looding t 

vary gre 
velopment 



to inunda 
e season, 
ing, the w 

type and 
the water 

and diver 
g decrease 
states tha 
tical grad 

sorted ou 
to their t 
ions in th 

condition 
adient, th 
s the phys 
that the d 
cy gradien 
eedling 
olerance o 
atly from 



tion 

the 

ater 

texture, 

flow. 

sity 

in 
t there 
ient 
t in 
olerances 
e 

s . 

e major 
ical 
istri- 
t may 

f 
their 



Hosner and Minckler (1963: 34) found that the bottomland 
tree species are associated with different ranges of soil 
moisture. For instance, the means of available moisture- 
holding capacity (expressed as the difference between mois- 
ture equivalent and wilting percentage) of the subsoil 
(61-76 cm, or 24-30 in) for the following bottomland 
species were box elder 14.21, cottonwood 14.62, pecan 14.97, 
sycamore 15.29, hackberry 15.91, and silver maple 16.32 
(Hosner and Minckler, 1963: 35). These moisture preferences 
parallel the moisture availability of different habitats. 
Hosner and Minckler (1963: 35) found that the mean available 
moisture constants of the subsoil (61-76 cm, 24-30 in) for 
five bottomland communities were newly-formed land 9.82, 
cottonwood-willow 15.13, mixed soft-hardwoods 16.76-, old 



5-7 



Vegetation 



fields 18.42, mixed hard-hardwoods 19.99, They found a 
similar trend in moisture constants in the topsoil (0-15 cm, 
0-6 in) of these communities. 

Bell (1974: 39) found that on floodplain areas ex- 
periencing flooding approximately 251. of the time, silver 
maple dominated strongly along with sycamore and green ash. 
He also found that silver maple represented more than 50° 
of the total individuals inhabiting elevations where 
flooding occurred more than 3-0 of the time. Johnson and Bell 
(1976b: 164) noted that silver maple also had the highest 
growth rates of any species in the bottomland forest. Bell 
(1974: 39) stated that green ash commonly coexists with 
silver maple, but is most abundant in areas flooded approxi- 
mately ^S% of the time. Bell (1974: 42) found that hack- 
berry occurs commonly at elevations that are flooded ap- 
proximately 3b of the time. He also found that American 
elm is important in areas with a flooding frequency of less 
than 2%. However, Hosner and Minckler (1960: 76) noted that 
elm was the most ubiquitous bottomland species and was 
found in respectable numbers under the widest range of 
conditions . 

The forest community in the floodplain has high primary 
productivity. Johnson and Bell (1976b: 163) state that the 
floodplain zone has relatively higher biomass and net pri- 
mary production even though tree species diversity is limited 
by the severe flood environment. However, these authors 
note that the floodplain environment is severe only during 
flood conditions when soil aeration is low. Johnson and 
Bell (1976b: 164) note that fertile soil, similar climatic 
conditions, and abundant soil moisture make the floodplain 
very suitable to those species adapted to periods of root 
inundation. 

Information gleaned from the literature concerning 
factors such as water levels, tolerances, and associated 
parameters for the primary bottomland tree species found 
along the Illinois River follows. 

Season of Flooding 

The general consensus of the papers reviewed con- 
cerning water tolerances of woody vegetation agree that 
the critical period for detrimental water level effects 
on woody vegetation is during the growing season -- 
approximately May through early October. Hall et al. 
(1946: 34), Hall and Smith (1955: 284), and Johnson and 



Vegetation 



Bell (1974: 35) concluded that flooding during the winter 
and early spring had limited adverse effects on bottomland 
forest and was not as critical as the profound effects 
flooding has during the growing season. Hall et al. 
(1946: 47) recommended dewatering 3 weeks before woody 
vegetation develops full foliage to prevent damage. 
Flooding of woody species during their dormant period may 
have minimal effects because of reduced oxygen requirements 
by the plants and higher oxygen concentrations in cold water, 
However, such factors as physical damage by ice movement 
and silt deposition can occur from high water during the non- 
growing season. 

Depth of Flooding 

Yeager (1949: 45) found that the depth of flooding 
did not appear to make much difference in mortality 
during the span of his study from 1938 to 1944. The 
majority of the species flooded had a 1001) mortality with 
an immersion of 2 to 25 cm (1 to 10 in) of water. He 
did find, however, that the mortality for the most water- 
tolerant species increased as the water depth increased. 

Green (1947: 120) concluded that the main factor 
in the tolerance of tree spe,cies to flooding appeared to 
be the relationship of the root crown to normal water 
levels. He found that for all tree species examined, as 
long as the root crown was permanently covered, the actual 
depth of water over the crown was of little importance. 
Green (1947: 120) found that trees standing in 1.2 m (4 ft) 
of water survived as well as those with only 5-10 cm 
(2-3 in) covering their root crown. Hall et al. (1946: 37) 
noted that the tree species that were the most tolerant 
of shallow inundation for long periods during the growing 
season were also the most tolerant of deep inundation. 
Hall et al. (1946: 55) also reported that completely sub- 
merged woody plants and their stumps did not produce sprouts 
while they were inundated. 



Duration of Flooding 

Yeager (1949: 42) found that the percentage of mor- 
tality for all tree species flooded increased with time in 
his investigation of bottomland forest along the Illinois 
River in Calhoun County. He found that most of all trees 
permanently flooded to a depth of 51 cm (20 in) or more were 
dead in 8 years and most were dead in 6 years when the water 



Vegetat i on 



5-9 



was above the root collar. Yeager (1949: 42) noted the 
following mortality rates: 33.7b of all flooded trees 
were dead after 2 years, 58°o after 3 years, 88.81> after 
4.5 years, and 93.5b after 6.5 years. 



Yeag 
and to a 
during th 
titious r 
under flo 
bear frui 
hawthorn, 
berry, sw 
during th 
elm, ash, 
the third 
that will 
crops whi 



er (19 

lesser 

e firs 

oots . 

oded c 

t. He 

swamp 

amp pr 

e seco 

river 

year 

ow, wa 

le but 



49: 

deg 
t tw 

Yea 
ondi 

not 

hoi 
ivet 
nd y 

bir 
afte 
ter 
tonb 



49) f 
ree , 
o yea 
ger ( 
tions 
ed th 

ly, 1 

, and 
ear a 
ch , a 
r flo 
locus 
ush p 



ound 
si Ive 
rs of 
1949: 
, som 
at tr 
ocus t 
butt 
fter 
nd pe 
oding 
t , an 
roduc 



that wi 
r maple 
f loodi 
49) di 
e tree 
ees or 
, cotto 
onbush 
f loodin 
can pro 
, Yeage 
d swamp 
ed a no 



How, 
, rea 
ng by 
scove 
speci 
shrub 
nwood 
bore 
g whi 
duced 
r (19 
priv 
rmal 



ash, 
cted 

grow 
red t 
es CO 
s of 
, wi 1 
appre 
le si 

smal 
49: 4 
et pr 
crop . 



but 
to h 
ing 
hat 
nt in 
pers 
low , 
ciab 
Iver 
1 cr 
9) n 
oduc 



tonbush , 
i gh water 
adven- 
even 
ued to 
immon , 

hack- 
le crops 

maple , 
ops. By 
oticed 
ed sparse 



Hosner and Boyce (1962: 80) expressed similar findings 
by noting that increased mortality and reduced growth were 
associated with increasing periods of continuous flooding 
depending upon the different susceptibility of the various 
species . 

Bell and Johnson (1974a: 29) noted that inundation during 
the growing season for under 30 days resulted in no mor- 
tality in established trees, upland species began dying 
after 60 days of flooding, and tolerant species completed 
their annual growth cycle after 189 days of flooding. Bell 
and Johnson (1974a:36) noted, however, that repeated annual 
flooding may lessen the tolerance of some species. 

Green (1947: 118) noted that trees permanently flooded 
along the Mississippi River showed little effect the first 
year. The second summer of flooding resulted in some 
die-offs and loss of vigor in some species. No species 
survived 4 years of constant flooding. Contrary to expec- 
tations. Green (1947: 120) found no decrease in the growth 
rates of trees permanently flooded as long as the trees 
lived. The growth rates compared favorably with the rates 
prior to flooding. However, they noted that when the trees 
did succumb, death was abrupt. 

In other studies. Hall and Smith (1955: 284) stated 
that all woody species were killed in Kentucky when they 
were flooded 54''b of the time during the growing season. 
Hall et al. (1946: 39) noted that 2 weeks of inundation can 
kill some trees if they are in full foliage. However, trees 



5-10 
Vegetati on 

defoliated by floods recover rapidly if dewatered after a 
short inundation period. Gill (1970: 676) noted that woody 
species cannot colonize areas flooded more than 401. of 
the growing season. 

Flooding Frequency 

Johnson and Bell (1976a:34) found that flood frequency 
had no significant effect on the growth rates of trees. 
However, they noted that the flood frequency was important 
in the establishment of trees with no effect after the 
trees reached 4 cm (1,6 in) in diameter. Hall et al. 
(1946: 37) proposed similar findings by noting that inter- 
rupted flood periods had little effect on tree species. 

Velocity 

Velocity of high water can also affect vegetation. 
Lindsey et al. (1961: 124) reported that flooding can 
cause mechanical injury such as lodging, removing leaves, 
and covering prostrate plants with debris and silt. Erosion 
caused by rapidly moving high water can undermine and 
eventually topple trees. It is also possible for some younger 
trees of water- tolerant species to become deformed from 
flood training by the current of moving water. Physical 
damage such as bark peeling could occur to trees by ice 
being transported by currents during high water conditions 
in the winter and spring months. However, flooding during 
the summer months by stagnant water resulting from little 
movement may be more injurious than flowing water because 
more oxygen enters flowing water. 

Elevation 

Raising water levels can affect woody vegetation in 
three different zones: the flooded zone where the trees 
become inundated; the new shoreline zone where the trees 
that were once removed from the water's edge now exist 
close to it and are susceptible to flooding; and the trees 
that are still on relatively high ground where they are 
flooded for only short, intermittent periods. 

The effects on the trees in the flooded zone are dis- 
cussed throughout this section on the bottomland forest. 
However, trees in the other two zones may show different 
effects . 



5-11 
Vegetation 



Trees along the new shoreline and other low areas after 
flooding may have well been above the original water level 
prior to flooding. Yeager (1949: 46) found that trees in 
this zone showed a less severe but parallel mortality rate 
to the trees that were flooded. However, he found that the 
reactions were slower in this region. Yeager (1949: 46) 
noted that except for the more water- tolerant species, 
50 to 100°c of the timber was dead in this zone 6 years 
after an increase in water levels. 

On high ground. Green (1947: 119) found that increased 
water levels had little effect on tree growth. Yeager 
(1949: 46) determined, however, that because permanent 
flooding resulted in a rise of the water table on land 
not actually flooded, timber stands were affected, but not 
always conspicuously. He noticed a slight increase in 
mortality in some species, but other species were not 
affected . 



Tree Size and Condition 

Yeager (1949: 43) found that tree diameter (age) ap- 
peared to make little difference in survival except in the 
5-cm (2-in) class. But this difference was a result of the 
semi-aquatic species in this size category. In general, 
healthy trees resisted flooding the best and the small and 
overmature trees appeared to be the most susceptible. 
Johnson and Bell (1976a: 36) expressed a similar view by 
finding that mortality rates from flooding were much higher 
in the suppressed-crown class of trees. Hall et al. 
(1946: 38) found that mature trees died more readily than 
immature. Hall et al. (1946: 37) also noted flooding 
damage in large trees appeared in the upper areas of the 
trees from early injury and in lower areas with added 
injury . 

Seedl ings 

Young trees, or seedlings, are also affected by flooding, 
if not more so than mature specimens. Yeager (1949: 40) 
believed that the flooding effect on seedlings was similar 
to the effect on parent trees. He noted that all but one 
species of seedlings were dead after 2 years in 0.3 m (1 foot) 
or less of water in areas flooded along the Illinois River. 
Hosner and Boyce (1962: 181) found that even 2.5 cm (1 in) 
of flooding for 60 days can kill first-year seedlings, but 
some species survived this treatment. Johnson and Bell 



Vegetation 



(1976a: 36) stated seedlings are most susceptible in their ' 
early stages of development before they reach 4 cm (1.6 in) | 
in diameter. j 

Briscoe (1957: 83) found that submersion of seedlings 
apparently reduced growth more than flooding and that the 
severity of the effects increased with the duration of sub- 
mersion and flooding. He also surmised that water tolerance 
increased with the age of the seedlings. Briscoe (1957: 83) 
determined that flooding reduced the shoot growth of seedling 
more than root growth, but submersion reduced root and shoot 
growth the same. 

Bell and Sipp (1975: 236) revealed similar findings. 
They found that the photosynthesis rate of first-year silver 
maple seedlings varied significantly and inversely with 
both the time of soil saturation and inundation. They 
determined that the growth rate of the seedlings was de- 
creased because the photosynthesis rate was reduced by 
about 25°o by soil saturation and approximately 75°* by 
inundat ion . 



Sediment Effects 

High water can result in a deposition of sediment in 
the bottomland forest. Turner (1929: 97) documented that 
the high waters of the 1926-27 flood of the Illinois River 
resulted in a deposition of alluvial soil that ranged from 
2-8 cm ( a few inches) to 0.6 m (2 ft) in depth. As a 
result of the accumulation of soil over the roots, high 
mortality occurred in several tree species. Howard and 
Penfound (1942: 284) noted that alluvial deposits up to 
0.3 m (1 ft) deep resulting from a flood killed both seed- 
lings and saplings of certain tree species. He believed 
that mortality varied with seedling size and the thickness 
of silt deposition. 



Soi 1 Texture 

Gill (1970: 674) notes that the soil texture of the 
flooded areas is important. He stated that the more clay 
that is present in the soil, the greater the amount of 
root anaerobiosis . Gill (1970: 674) also noted that 
indirect effects like toxin accumulation are worse in 
heavy soils. 



5-13 
Vegetation 

Flooding and Water Tolerances of Bottomland Tree Species 

Yeager (1949: 49) summarized the effects of a permanent 
1 -m (3-ft) rise in the Illinois River on the bottomland 
forest near Grafton, Illinois. He noted the following 
periods required to kill all trees of various species: 
2 years killed all of the pin oaks; 3 years removed bur oak, 
hackberry, persimmon, and river birch; 4 years killed haw- 
thorn, Cottonwood, and swamp holly; 5 years removed silver 
maple and American elm; 6 years removed pecan; 7 years 
killed water locust; and 8 years of flooding killed ash, 
buttonbush, and most of the swamp privet and black willows. 
Yeager (1949: 42) noted that after 2 years of flooding the 
species with the highest rates of dying were river birch 
(76.5-0, but only 4 were in his study area), pin oak (71.4°), 
hawthorn (56.21), and silver maple (43.51,). Yeager (1949: 
47) determined that pin oak was easily the species most sus- 
ceptible to injury by flooding. Bell and Johnson (1974a: 31) 
found that black oak was the least flood- tolerant of the 
species they investigated. 

Flooding Tolerances of Tree Species 

The following studies investigated the comparative 
effects of flooding on tree species that occur in the 
project area: Hall et al. (1946), Green (1947), Yeager 
(1949), Lindsey et al. (1961), and Bell and Johnson (1974a). 
Summarizing the water tolerance classifications presented 
in these studies, we categorized the tree species into 
tolerant, moderately tolerant, and intolerant groups 
(Table 5-1). Individuals in the intolerant group would 
probably be the first to die during the first or second 
growing season from the effects of increased water levels, 
individuals from the moderately tolerant group may survive 
until the second, third, or possibly fourth growing season, 
and some individuals from the tolerant group would probably 
be the last to expire and might live several growing seasons 
in the shallow flooded areas. 

A brief description of the water tolerances of the 
various tree species likely to occur in the project area 
follows. The descriptions are summarized for the species 
that were described in the scientific literature. 

Intolerant Species 

Black Oak . Highest mortality rate of species investi- 
gated"!^ Did not survive 89 days of flooding (Bell and 
Johnson, 1974a: 30). 



5- 



Table 5-1. Classification of Water Level Tolerances of 

Tree Species that may occur in the Project Area. 



Intolerant Moderately Tolerant Tolerant 

Black oak Honey locust Water locust. 

Red oak Box elder Swamp privet 

Shingle oak Silver maple Black willow 

Pin oak Hawthorn Buttonbush 

Blackjack oak American elm 

White oak Cottonwood 

Bur oak Pecan 

Chinquapin oak Sycamore 

Black walnut Red mulberry 

Shagbark hickory Swamp holly" 

Mockernut hickory Green ash 

Bitternut hickory River birch 

Shellbark hickory 

Sugar maple 

White ash 

Black cherry 

Hackberry 

Sugarberry 

Black locust 

Red bud 

Basswood 

Ohio buckeye 

Persimmon 



Categories based on data presented in Hall et al. (1946), 
Green (1947), Yeager (1949), Lindsey et al. (1961), and 
Bell and Johnson (1974a). 

Shrubs or small trees. 



5-15 



Vegetation 



Red Oak 



letter survival than black oak but did not 



survive 160 days of flooding (Bell and Johnson, 1974a: 30). 

Shingle Oak . Similar to red oak; did not survive 
160 days of flooding (Bell and Johnson, 1974a:30). 

Pin Oak . Started dying in one year when flooded 
(Yeager, 1949: 47). Flooding for more than 40% of the growing 
season results in mortality (Turner, 1929: 97; Hall and 
Smith, 1955: 284). 

White Oak . Similar tolerance to those of red and 
shingle oaks. Failed to survive 149 days of flooding 
(Bell and Johnson, 1974a:30). 

Bur Oak. Better tolerance than red, white, black. 



and shingle oaks and survived 189 days of flooding 

(Bell and Johnson, 1974a: 35). All were dead 4 years after 

flooding (Yeager, 1949: 42). 

Black Walnut . Severe effects resulted when inundation 
reached 110 days (Bell and Johnson, 1974a: 33). May not 
survive in 0.3 m (1 ft) of water for 1 growing season 
(Hall et al. , 1946: 35) . 

Shagbark Hickory . Some individuals were alive after 
150 days of inundation (Bell and Johnson, 1974a: 32). May 
not survive in 0.3 m (1 ft) of water for 1 growing season 
(Hall et al., 1946: 35). Death resulted if flooded more 
than 22-0 of the growing season (Hall and Smith, 1955: 284). 

Mockernut Hickory . More sensitive than shagbark hick- 
ory. None survived 109 days of inundation (Bell and 
Johnson, 1974a:32). 

Sugar Maple . Very intolerant of flooding and will 
not survive in 0.3 m (1 ft) of water for 1 growing season 
and may succumb in less than 1 month (Hall et al., 1946: 35) 

White Ash . Will not survive in 0.3 m (1 ft) of water 
for 1 growing season and may not last 1 month (Hall et al., 
1946: 35). 

Hackberry . Some individuals died after 129 days of 
flooding and all were dead after 189 days (Bell and Johnson, 
1974a: 35). Died if they were flooded for 251 of the 
growing season (Hall and Smith, 1955: 284). 



Vegetation 



;lack Locust. Will not survive in 0.3 m (1 ft) of 



water for 1 growing season and may not last 1 month (Hall 
et al. , 1946: 35) . 

Red Bud . Will not survive in 0.3 m (1 ft) of water for 
1 growing season and may not last 1 month (Hall et al., 
1946: 55). 

Moderately Tolerant Species 

Honey Locust . Showed no effects after 189 days of 

inundation (Bell and Johnson, 1974a: 33). Survived 0.3 m 

(1 ft) of water for 2 growing seasons (Hall et al., 1946: 
36) . 

Box Elder . Showed no effects after 189 days of 
inundation (Bell and Johnson, 1974a:33). Survived 1 

growing season but not 2 in 0.3 m (1 ft) of water (Hall 
et al. , 1946: 56) . 

Silver Maple . Showed no effects after 189 days of 
inundation (Bell and Johnson, 1974a: 33) . Some mortality 
occurred in second summer of constant flooding (Green, 
1947: 118). Survived as much as 2 growing seasons in 
0.3 m (1 ft) of water (Hall et al., 1946: 36). 

Hawthorn . Survived 189 days of inundation (Bell and 
Johnson, 1974a:33). Survived 1 growing season but not 2 
in 0.3 m (1 ft) of water (Hall et al., 1946: 36). 

American Elm . Approximately 501. mortality occurred in 
1 m (3 ft) of water in 4 years (Yeager, 1949: 42). Mor- 
tality occurred in 0.5-1.2 m (1.5-4 ft) of water after 2 
years (Green, 1947: 118). Survived 1 but not 2 growing 
seasons in 0.3 m (1 ft) of water (Hall et al., 1946: 36). 

Cottonwood . Approximately 506 mortality occurred in 
1 m (3 ft) of water in 4 years (Yeager, 1949: 42). Most 
individuals were dead after 2 years in 0.5-1.2 m (1.5-4 ft) 
of water (Green, 1947: 118). Survived 2 growing seasons 
m 0.3 m (1 ft) of water (Hall et al., 1946: 36). Indi- 
viduals began dying if flooded more than 35-0 of the growing 
season (Hall and Smith, 1955: 284). 

Pecan. Complete mortality after 6 years in 0.1 m 
(3 ft) of water with 501 mortality by the fourth year. 
All were dead in 5 years along the new shoreline zone 
(Yeager, 1949: 42). 



5-17 



Vegetation 



Sycamore . Survived more than 169 days of flooding 
(Bell and Johnson, 1974a: 33). Survived 1 but not 2 growing 
seasons in 0.3 m (1 ft) of water (Hall et al., 1946: 36). 

Red Mulberry . Survived 1 but not 2 growing seasons 
in 0.3m (1 ft) of water (Hall et al . , 1946: 35). 

Swamp Holly . Survived 1 but not 2 growing seasons in 
0.3 m (1 ft) of water (Hall et al., 1946: 35). Mortality 
began when flooded more than 40° of the growing season 
(Hall and Smith, 1955: 284). 

Green Ash . Survived 2 growing seasons in 0.3 m (1 
ft) of water (Hall et al., 1946: 36). Individuals were 
hardy after 2 years in 0.5-1.2 m (1.5-4 ft) of water 
(Green, 1947: 118). Mortality occurred after 17 months in 
1 m (3 ft) of water, but lived longer than most species 
(De Gruchy, 1959: 45) . 

River Birch . Had a high rate of dying with 76.51 
dead after 2 years of flooding (Yeager, 1949: 42). 

Tolerant Species 

Water Locust . Semiaquatic -- mortality reached 96d 
after 6 years in 1 m (3 ft) of water with 501> mortality 
by the third year (Yeager, 1949: 42). 

Swamp Privet . Relatively resistant to flooding -- 
mortality reached 85'o after 8 years in water with 501 
mortality by the fourth year (Yeager, 1942: 41), Sur- 
vived 2 growing seasons in 0.3 m (1 ft) of water (Hall et 
al., 1946: 36). 

Black Wi How . Well adapted to water -- mortality 
reached 611 after 8 years in water with 401 mortality by 
the sixth year (Yeager, 1949: 42). Thriving after 3 years 
in 0.5-1.2 m (1.5-4 ft) of water but 100° mortality in 5 
years (Green, 1947: 118). Survived 2 growing seasons in 
0.3 m (1 ft) of water (Hall et al., 1946: 36). 

Buttonbush . Survived 0.6 m (2 ft) of water for 7 
years (Hall et al . , 1946: 36). Mortality reached 60o 
after 6 years in water (Yeager, 1949: 42). 



Field Inventory of Bottomland Forest 

During October, 1978, 13 representative tracts of 
bottomland timber were cruised from Hennepin to Grafton 



5-18 



Vegetation 



Four of these forests were in the Peoria Pool, 5 were in 
the La Grange Pool, and 4 were in the Alton Pool (Figure 5-1). 
In addition, Tom Sanford, U.S. Fish 5 Wildlife Service, 
Chautauqua Refuge, provided data from 1977 for 2 areas of 
bottomland timber in the Mark Twain National Wildlife 
Refuge, Mcredosia Division, in the Alton Pool. Also, data , 
were taken from Nixon et al. (1978d: 18) for a bottomland 
timber cruised in 1976 in Mason County, La Grange Pool. 
A variety of areas were sampled; 7 areas were privately 
owned, 7 areas were owned by the state, and 2 areas were on 
federal property. Five of these areas occurred on islands. 

Variable plot cruising with a 10-factor basal area 
prism along transects was used to gather data on species 
composition, basal area, density, tree size (diameter breast 
height, DBH) , and volume. Data were collected at a minimum 
of 40 sampling points 60 m (66 yds) apart in the majority 
of the forests sampled. Sampling procedures and data analysis 
were performed according to Dilworth and Bell (1977). 
Sav.'timber volume (board feet per acre) was based on trees 
with a minimum 31-cm (12-in) DBH. Both the International 
and Doyle Rule for determination of sawtimber volume were 
used. Monetary values for sawtimber stumpage volume were 
taken from "Illinois Timber Prices" published 25 May 
1978, by the Illinois Division of Forestry. 

The bottomland forest areas sampled are shown in 
Figure 5-1 and the data tabulated for each area are pre- 
sented in Tables 5-2 through 5-17. The topography of all 
the areas sampled was flat. 

A total of 18 tree species was tallied in the timber 
cruises. Silver maple, cottonwood, and ash spp. were found 
in all 16 forests. Elm spp, were found in all the areas 
except one. Willow spp., hackberry, and pecan were 
found in 9 of the 16 areas. Sycamore occurred in 6 areas 
whereas box elder was noted in 5. The remaining species -- 
river birch, honey locust, red mulberry, basswood, haw- 
thorn spp,, pin oak, persimmon, sugarberry, and swamp 
privet -- were found in 4 (251) or less of the forest 
areas sampled. The mean number of tree species occurring 
on the study areas was 7.6. All but 3 areas had 8 or 
fewer species. The Glades State Conservation Area had the 
most species with 15, Godars Swamp State Conservation Area 
had 11 species, and Big Blue Island had 10 tree species 
present. All of these areas are in the Alton Pool 
(Figure 5- 1 ) . 



5-19 



UKE KICHIGAN 




1 - HENNEPIN 

2 . BIG SPPING 

3 - KARSBSU COUNTY CONSEBVATIOH ABEt 
i - SPRING BRANCH COVSERVATION AREA 

5 - DUCK ISLAND 

6 - CLEAR LAKE 

7 - GRAND ISLAND 

8 - SANGASOIS CONSERVATION AREA 

9 - SANGANDIS CONSERVATION AREA 

10 - LYNCHBURG TOWNSHIP 

11 - MEREDOSIA NATIONAL WILDLIFE REFUGE 
1? - MEREDOSIA NATIONAL WILDLIFE REFUGE 
13 - BIG BLUE ISLAND 

la - GDDABS SWAMP STATE CONSEBVATIOS AREA 
15 . THE GLADES STATE CONSERVATION AREA 



25 50 
1ILES 



50 

KILOMETERS 



Figure 5- 1 



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the project boundaries of the Illinois River 
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Vegetation 



The density of bottomland trees varied from 232 to 742 
trees per hectare (95- 303/acre) among the study sites with 
an average of 419 trees/ha (170/acre) for all the areas. 
The area with the smallest density of trees was in the 
Meredosia Division of the Mark Twain National Wildlife Refuj 
(Area 11 in Figure 5-1 , Table5-12). This area had the 
largest trees inventoried with an average DBH of 66 cm 
(25.8 in), whereas the average DBH's for the remaining 
areas ranged from 31 cm (12.2 in) to 45 cm (17.9 in). 
The area with the greatest density of trees was Big Blue 
Island in the Alton Pool (Area 15 in Figure 5-1 , Table 5-14). 
The high density of trees on Big Blue Island was a result 
of the abundance (363/ha, 147/acre) of small elm trees 
(13 cm DBH; 5 in). Silver maple had the greatest density 
on 13 of the 16 areas investigated and elm spp. had the 
highest density on the remaining 3 areas. Overall, silver 
maple accounted for an average of approximately 521 of the 
tree densities, and elm spp., ash spp., and cottonwood 
averaged approximately 18°, 6.5^o, and 4.5&, respectively, 
of the tree densities on the areas sampled. 

The basal area of the bottomland timber stands sampled 
varied between 21.8 and 39.6 m'^/ha (95.0 to 173 ft^/acre) 
with an overall mean of 30.9 m2/ha (134.8 ft^/acre) . The 
area with the smallest basal area was- a privately owned 
forest near Hennepin (Area 1 in Figure 5-1 , Table 5-12) 
that had been logged sometime during the past decade. Island 
525 (Area 16 in Figure 5-1 , Table 5-17) at Calhoun Point 
State Conservation Area had the largest basal area of the 
forests sampled. Silver maple accounted for the majority 
of the basal area in the areas studied with an average of 
61.4°6 for all the areas. Cottonwood, ash spp., and elm spp. 
accounted for an overall average of 11.81, 5.31, and 4.81, 
respectively of the basal areas of the forests investigated. 

The sawtimber stumpage value was estimated for 13 of 
the forests sampled. The sawtimber value per thousand 
board-feet per acre (volume) ranged between $28 and $40 
for most of the bottomland tree species inventoried. How- 
ever, the price for ash spp. was $76 per thousand board- 
feet. The value for sawtimber in the bottomland stands 
sampled varied between $628/ha ($254/acre) and $1,469/ha 
($595/acre) using the International Rule of calculation 
and between $578/ha ($234/acre) and $l,354/ha ($548/acre) 
using the Doyle Rule. These estimates should be considered 
as maximum amounts. An average sawtimber value for the 
13 areas sampled for volume was $968/ha ($392/acre) cal- 
culated by the International Rule and $892/ha ($361/acre) 
using the Doyle Rule. Silver maple contributed the 
majority to the sawlog values, roughly 60'o, with cottonwood 



5-37 



Vegetation 



and ash spp. providing approximately ^7% and 101, respectively, 
to the lumber estimations. Therefore, these 3 species ac- 
counted for roughly 871, of the sawlog values in the forests 
sampled. The forest with the highest sawlog price was lo- 
cated in the Sanganois Conservation Area (Area S in Figure 5-1, 
Table 5-9 ) where the confluents of the Sangamon and 
Illinois rivers unite. This area had the most ash trees 
of the areas sampled. Large individuals of pin oak (102 
cm DBH; 40 in), silver maple (137 cm DBH; 54 in), pecan 
(81 cm DBH; 32 in), and river birch (46 cm DBH; 18 in) 
were also found in this area, although these specific indi- 
viduals did not occur in our sampling plots. 

Perhaps the most impressive forest stand sampled was 
Godars Swamp State Conservation Area (Area 14 in Figure 5-1 , 
Table 5-15) in the Alton Pool. Here large, magnificent pecan 
trees accounted for 306 of the basal area. Some of these 
pecan trees had DBH's of 91 cm (36 in). A good population 
of large Cottonwood trees and a fair number of pin oaks were 
also present. 

Timber on or nearby at least 5 sampling areas was 
currently being or had been harvested during the past 10 
years. Because of present and past selective timber har- 
vesting and agricultural encroachment, as well as the 
increased water levels in the Illinois River via the diver- 
sion of water from Lake Michigan and construction of dams 
during the first 40 years of this century, the majestic, 
fruitful, and diverse pecan and pin oak stands once prevalent 
in the bottomlands along the river from approximately Peoria 
southward were and are being transformed to forests less 
diverse and dominated by silver maple. Both pecans and pin 
oaks are valuable to several species of wildlife 
for both food and shelter (den cavities). However, we found 
sparse numbers of pecans in 9 of the areas we inventoried 
and we found pin oaks in only 4. The diversity of plant 
communities often dictates the diversity and population 
levels of their associated animal species. Therefore, any 
factors, whether natural or artificial, that reduce the di- 
versity or complexity of the bottomland plant communities 
will indirectly adversely affect the associated faunal popu- 
lations. Thus, as long as the Illinois River bottomland 
forests continue to be degraded, the populations of most 
wildlife species can be expected to deteriorate. Silver 
maples do produce seeds used by wildlife and also provide 
tree cavities for nurseries and shelter. Tom Sanford, U.S. 
Fish and Wildlife Service, found between 20 and 35 den 
cavities/ha (8-14/acre) in 2 bottomland forest areas at 
Meredosia (Areas 11 and 12 , Figure 5-1). Practically all 



Vegetation 



of these cavities occurred in silver maples. However, the j 
silver maple forests of today undoubtedly are not of similar 
value to wildlife species as the pecan-pin oak bottomlands | 
of yesterday. Originally, the undisturbed bottomland forestsl 
that typified the Illinois A'^allev was excellent wildlife hahiai 
and contained a mixture of silver maples, pecans, pin oaks, li 
several other species. Unfortunately, only a few tattered j 
and scattered remnants of these grand bottomland forests ! 
still linger in the southern reaches (Alton Pool) of the i 
Illinois River. I 



Effects of Diversion 

Permanent flooding of the bottomland community would 
result in the death of the inundated woody species in con- 
gruence with their inherent water tolerances. Continuous 
flooding during the growing season becomes damaging for 
periods over 2 weeks in duration for water-sensitive species 
The critical depth of water appears to be the level (less 
than 51 cm or 20 in) that covers the root crowns of the 
trees. Yeager (1949: 45) noted a complete mortality of 
several tree species with just 2-25 cm (1-10 in) of water 
covering the ground. Thus, a small amount of water for 
periods longer than 2 weeks can begin to change the bottom- 
land forest communities. Of course, the longer the duration 
of inundation, the greater the magnitude of damage. Inun- 
dation for half or more of the growing season during 4 to 
8 consecutive years will practically eliminate the majority 
of bottomland tree species with possible exceptions of 
extremely water- tolerant species such as black willow, swamp 
privet, water locust, and buttonbush. Turner (1929) noted 
that after the floods of the Illinois River in the fall of 
1926 and the spring of 1927, approximately 901 of pin oaks, 
cottonwoods, and elms were killed resulting in the deaths 
of hundreds of acres of bottomland forest. Pecans, maples, 
and walnuts also suffered mortality. Yeager (1949) found 
that 8 years of flooding along the lower Illinois River 
resulted in practically complete tree mortality. Turner 
(1929) also noted that honey locusts, elms, maples, and pin 
oaks were killed by the smothering effects of substantial 
amounti> of soil that was deposited over the roots of these 
trees by flood waters. 

The computer models of proposed diversion rates of 
6,600 and 10,000 cfs for 1971, 1973, and 1977 permitted 
investigation of possible bottomland forest inundation. 
The computer models provided water level information for 
the Henry (Peoria Pool) and Havana (La Grange Pool) gauges. 



5-39 



Vegetation 



The gr 

sensi t 

until 

Havana 

Weathe 

these 

levels 

predic 

divers 

then c 

increa 

vana g 

locali 

would 

are va 

tively 

each p 

accord 



owing seas 
ive to inu 
1 October. 

for this 
r Service 
actual riv 

for this 
ted by the 
ion took p 
ompared th 
se from th 
auges with 
ties to de 
have occur 
lid for th 
, because 
ool and th 
ance with 



on when 
ndati on 

The ac 
entire g 
stage re 
er level 
growing 

compute 
lace dur 
ese wate 
e propos 

the ele 
termine 
red. Th 
e entire 
these ga 
e elevat 
the elev 



bott 

exte 

tual 

rowi 

cord 

s we 

seas 

r mo 

ing 

r le 

ed d 

vati 

if i 

ese 

Peo 
uges 
ion 
atio 



omla 
nds 

ave 
ng s 
s f o 

add 
on t 
dels 
thes 
vels 
iver 
on o 
nund 
comp 
ria 

are 
of t 
n of 



nd t 
appr 
rage 
easo 
r 19 
ed t 
hat 
. if 
e th 

(th 
si on 
f th 
atio 
aris 
and 

cen 
he t 

the 



ree speci 
oximately 

river le 
n was cal 
71, 1973, 
he averag 
would hav 

the 6,60 
ree years 
e actual 
s) at the 
e tree li 
n of bott 
ons at He 
La Grange 
trally lo 
ree line 

river . 



es are highly 

from 30 April 
vel at Henry and 
culated from U.S. 

and 1977. To 
e rise in water 
e occurred, as 
0- and 10,000-cfs 

(Table5-18). Ke 
average plus the 

Henry and Ha- 
ne at these 
omland forests 
nry and Havana 

pools, respec- 
cated within 
changes in 



At Henry in the Peoria Pool, the actual riv 
for the 30 April- 1 October growing season average 
tree line (441.6 ft) in 1971 (440.9 ft], above th 
line in 1973 (443,9 ft), and slightly below the t 
1977 (441.3 ft) (Table5-18). The 6,600-cfs diver 
have increased water levels an average of 0.27 m 
above the tree line for the 30 April-1 October gr 
in 1971, an average of 1.13 m (3.7 ft) above the 
1973, and an average of 0.43 m (1.4 ft) above the 
in 1977 (Table 5-18). The 10,000-cfs diversion wo 
raised the water level at Henry to an average 443 
this growing period in both 1971 and 1977 which w 
overtopped the tree line by 0.70 m (2.3 ft). No 
diversion would have occurred in 1973. Consequent 
these proposed diversion rates would have inundat 
land forest, consisting mainly of silver maple, c 
elms, ash, and willow trees, and would have had d 
effects during the same growing season on all but 
These negative effects would be compounded if inu 
occur in consecutive growing seasons. 



er levels 
d below the 
e tree 
ree line in 
sion would 
(0.9 ft) 
owing season 
tree line in 

tree line 
uld have 
.9 ft during 
ould have 
10,000-cfs 
ly, both of 
ed bottom- 
ot tonwoods , 
eleterious 

the willows, 
ndation would 



At Havana in the La Grange Pool, the proposed in- 
creased diversions would not have resulted in as much inun- 
dation. The averages for the actual river levels at Havana 
were 431.0, 436.5, and 432.6 ft, respectively, for 1971, 
1973, and 1977 as compared to the tree line elevation of 
434.4 ft (Table 5-18). Thus, the actual river levels for the 
30 April-1 October growing season averaged 1.04 m (3.4 ft) 
and 0.55 m (1.8 ft) below the tree line in 1971 and 1977, 
respectively, but 0.64 m (2.1 ft) above the tree line in 1973 



5-40 



Table 5-18. Average Gauge Readings in msl (ft) for Henry 

(Peoria Pool) and Havana (La Grange Pool) calcu- 
lated from the U.S. Weather Service River Stage 
Records with the Addition of the Increase in 
Water Levels as Predicted by the Computer Models 
for the 6,600- and 10,000-cfs Diversion. The 
Gauge Readings are for the Entire Growing Period 
of 30 April-1 October, 1971, 1973, and 1977. 



Year 



1971 



1973 



1977 



Average 
Gauge Reading 
msl (ft) 



Average Gauge Average Gauf 
Reading Plus Reading Plus 
6,600-cfs Diversion 10,000-cfs 
msl (ft) msl (ft) 



Henry (Peoria Pool) 



440.9 



443.9 



(1.6) 



1 


— (1.4) 


441 .3 




I 


— (1.7) 



442.5 



•(3.0> 



445.3 



443.0 



(2.6)- 



(1.4)- 



■(0.9)- 



443.9 



443.9 
J 



1971 



1973 



1977 



Havana (La Grange Pool) 

431.0 432.8 433.9 
1 (1 .8) (« (1 . 1) < 



-(2.9)- 



436.5 438.2 
' (1.7) • 

432.6 434.2 434.8 
i (1 .6) •> (0.6) ' 

' (2.2) . 



Differences 



5-41 



Vegetation 



(Table 5-18). Only the 6,600-cfs diversion in 1973, resulting 
in an average river level of 438.2 ft or 3.8 ft above the 
tree line and the 10,000-cfs diversion in 1977, resulting in 
an average river level of 434.8 ft or 0.4 ft above the tree 
line, would have inundated the bottomland forest (Table 5-18). 
Thus, the bottomland forest communities in the La Grange 
Pool would not have been as drastically affected by the 
increased diversions as those in the Peoria Pool because of 
the differences in the configurations of the bottom contours 
between the pools (see Chapter 4 ). The 1.16-m (3.8-ft) 
increase above the tree line as a result of the 6,600-cfs 
diversion in 1973 would have had devastating effects on the 
bottomland forest communities. The increase of 0.12 m 
(0.4 ft) above the tree line by the 10,000-cfs diversion in 
1977 would have had more limited detrimental effects on most 
bottomland tree species in the La Grange Pool depending upon 
differential water tolerances of the species, the duration of 
inundation, and minor elevational differences within the bot- 
tomland communities. However, this amount of inundation (0.12 
m; 0.4 ft) is still enough to cover the root collars of the 
bottomland trees and thus result in mortality of the more 
sensitive species if inundation would persist. 

Death of bottomland forest would probably result in a 
shift of the various woody vegetational zones landward. The 
flooded area would probably consist of dead and fallen timber. 
If the proper water quality conditions exist (such as low 
turbidity) , the area may begin to succeed to marsh as Yeager 
(1949: 54) found in Calhoun County. He reported that plants 
such as cattails ( Typha latifolia ) , duck potato ( Sagittaria 
spp.), smartweeds ( Polygonum spp.), rice cutgrass ( LeersiT " 
oryzoides ) , and others began to appear after a number of 
years. Correspondingly, Yeager (1949: 46) believed that 
willow, Cottonwood, and ash would become established on the 
new shorelines. Thus, there would eventually be a distribu- 
tion of tree species from the new shoreline to the new upper 
flood limit according to their tolerance of flooding. 

As Klein et al. (1975: 91) indicate, the migration or 
establishment of woody communities in the landward direction 
depends upon the topographic gradients adjacent to the new 
water levels. If the gradient were level, the communities 
could be displaced with possibly the net loss of forest 
being proportional in each community (Klein et al., 1975: 
91). A steep gradient could result in little or no flat 
areas to be inundated, thereby greatly curtailing or elimina- 
ting the flood-tolerant communities. Other variations of 
these examples could exist which would result in various 
proportions of flood- tolerant and non-tolerant communities. 



5-42 
Vegetati on 



One important consideration, however, is the narrowness of 
the band of bottomland timber that exists along most of the 
Illinois River. The land adjacent to the river has been 
heavily cleared, farmed, or developed as close to the river 
as possible, thus leaving only a thin strip of forest in 
many areas. Therefore, any increase in water levels in 
these areas would probably result in a decrease in forest 
because of the reduction of land between the new shoreline 
and the margins of established agricultural fields, roads, 
or other developments. However, a rise in the water table 
may prohibit farming and other activities to continue to 
the limits of the previously established boundaries. 

Another factor to consider is the rapid rate of sedimen- 
tation that is presently occurring in the Illinois River. 
If water levels are raised, after a period of time, areas 
of sediment deposition will begin to form. These new areas 
should provide areas for establishment of the early succes- 
sional bottomland tree species -- black willows and cotton- 
woods. Thus, although high water levels would undoubtedly 
remove many acres of bottomland timber that presently occur 
along the Illinois River, we may regain some of the bottom- 
land forest as time passes through sedimentation and suc- 
cession if these areas do not become cleared for agricultural 
or other purposes. However, it could take a minimum of 
approximately 60-100 years for siltation and succession to 
create a habitat that approaches the diversity, composition, 
and other qualities (although often poor) of the existing 
bottomland forests that would be lost to increased water 
levels. Overall, a decrease in the amount of bottomland 
timber would undoubtedly occur if water levels are increased. 

Another change in the bottomland forest communities 
would occur on the islands in the Illinois River. A rise in 
water levels could possibly inundate entire islands because 
they are generally flat and often slightly lower in elevation 
than the shoreline floodplain. Thus, most of the trees 
would eventually expire and there would be no adjacent land 
on which water- tolerant species could become re-established. 
Recovery of bottomland forests on these islands would probably 
be dependent on sedimentation to reconstruct areas suitable 
for recoloni zation around or on the original islands, 

SHRUBS I 

! 

The species of shrubs that occur in the bottomland ! 
forest in the Illinois River valley may vary somewhat from 
area to area. Such factors as the amount of light reaching 



5-43 



Vegetation 



the forest floor, soil moisture, flooding, and plant compe- 
tition affect the species composition of the shrub strata. 
Shrub populations may often be low or poorly developed, 
possibly because of unsatisfactory germination conditions 
(flooding, especially in low areas, or shading). 

Most of the tree species that occur in the overstory of 
the bottomland forest are also present in the shrub strata. 
Such tree species as willow, cottonwood, elms, ashes, box 
elder, silver maple, hackberry, sycamore, swamp privet, 
and others are commonly found in the shrub zone. 

Hosner and Minckler (1960: 76) noted that most of the 
major species found in bottomlands germinate and become 
established in a wide range of site and soil conditions 
with the exception of cottonwoods and willows that require 
areas of sparse ground cover. They stated (1960: 76) that 
with most bottomland tree species, reproduction appeared to 
be reduced in areas where the ground cover was dense and/or 
the overstories sparse and also in areas where a deep litter 
layer occurred. Hosner and Minckler (1960: 73) found that 
box elder, hackberry, and American elm occurred in bottom- 
land areas with medium and heavy plant competition whereas 
silver maple and ash seedlings usually occurred in all 
cover types but were reduced in numbers in areas with 
dense vegetation. Hosner and Minckler (1960: 76) believed 
that American elm, box elder, silver maple, and green ash 
are able to compete over a wide spectrum of environmental 
conditions because they are common as seedlings in various 
stands of bottomland forest. 



Some of 
bottomland fo 
vines such as 
spp. ) , Virgin 
berries ( Rubu 
greenbriar (^ 
and bitterswe 
which may fre 
canadens is ) , 
( Forest: era a 
pureus ) , butt 
ciduous holly 
the shrubs li 
in Table C-2 



the other common sh 

rest in the Illinoi 

poison ivy ( Rhus r 

ia creeper ( Parthen 



rubs found thr 
s River valley 
adicans ) , grap 
ocissus quinqu 



oughout the 

are woody 
e vines ( Vi t i s 
efolia) , 



s^ spp.), trumpet-cr 
mi lax spp.), bluevi 
"et f Celastrus scand 
quently occur are c 
smooth sumac ( Rhus 
cuminata ) , burning 
onbush ( Cephalanthu 
(Ilex decidua7~! A 



kely to occur in th 
in the appendices. 



eeper ( Campsis 
ne ( Ampelamus 
eus ) . Other s 
ommon elder (S 
glabra ) , swamp 
bush ( Euonymus 
s occ idental is 
more complete 
e project area 



radi cans ) , 
albidus ) , 
hrub species 
ambucus 



privet 
atropur - 
) , and de- 
listing of 
is presented 



5-44 



Vegetation 



1978 Field Inventory 



No 
for thi 
encount 
Chautau 
1977 (A 
trees p 
grapevi 
I llinoi 
in a bo 
5-1) du 
Many of 
through 
valley . 
elm spp 
tively , 
DBH <10 
a DBH < 



speci 
s inve 
ered . 
qua Re 
rea li 
resent 
nes (V 
s N a t u 
tt omla 
ring 1 

the s 

out th 

They 

. , but 

were 

cm (4 
2 . 5 cm 



fie s 
stiga 

Tom 
fuge, 
in 

in t 
i tis 
ral H 
nd fo 
978, 
pecie 
e bot 

disc 
tonbu 
the m 

in) 

(1 i 



hrub i 
tion. 
Sanf or 

found 
Figure 
hat bo 
spp.) . 
istory 
rest a 

The i r 
s they 
tomlan 
overed 
sh, sw 
ost fr 
at Gra 
n). 



nven 
How 

d, U 
tha 
5-1 

ttom 

Dr 

Sur 

t Gr 
res 
f ou 

d fo 
tha 

amp 

eque 

nd I 



tory 
ever 
.S. 
t at 
), 4 
land 
s. R 
vey, 
and 
ults 
nd i 
rest 
t gr 
priv 
ntly 
s Ian 



or sampling 
, two source 
Fish and Wil 

a Meredosia 
Ob of the ba 

forest cont 
ichard and J 

sampled the 
Island (Area 

are present 
n the shrub 
s in the 111 
ape, ash spp 
et, and pois 

occurring s 
d. Most of 



was performed 
s of data were 
dlife Service, 

study area in . 
sal area of 
ained live 
ean Graber, 

shrub strata 

7 in Figure 
ed in Table j-19. 
strata are typical 
inois River 
. , silver maple , 
on ivy, respec- 
hrubs with a 
the shrubs had 



Effects of Diversion 



Because a ma 
within the projec 
fects of increase 
cussed throughout 
through 5-41) . Th 
water levels are 
older individuals 
water locust, but 
the most water-to 
upon flooding dur 
tors discussed pr 
shrubs that are v 
briar and grape s 
inundation (proba 
not 2 of continuo 
whereas trumpet-c 
could survive flo 
Continuous floodi 
periods or freque 
in the shrub stra 
possibly result i 
story if water le 
during the growin 



jority of the shrubs in the bottomlands 
t area are young trees, many of the ef- 
d diversion on the shrub strata are dis- 

the bottomland forest section (pages 5-1 
e tolerances of the young trees to higher 
somewhat similar to their tolerances as 

(Table 5-1 ) . Generally, black willow, 
tonbush, and swamp privet are probably 
lerant shrubs or small trees depending 
ation, frequency, depth, and other fac- 
eviously (pages 5-6 to 5-12) . As for 
ines. Hall et al. (1946: 36) found green- 
pp . to be moderately tolerant of 
bly could survive 1 growing season but 
us flooding 0.3 m C\ ft^ or more deep) 
reeper was tolerant of flooding (probably 
oding for as much as 2 growing seasons) . 
ng during the growing season for lengthy 
nt flooding may reduce the number of species 
ta as well as in the overstory. This could 
n more herbaceous vegetation in the under- 
vels fell and exposed the soil early enough 
g season for establishment. 



5-45 



Table 5-19. Percent Frequency of Occurrence of Woody Understory 
Plants £lO cm (4 in ) DBH in Bottomland Forest on 
Grand Island (La Grange Pool), 1978. ^'^ 



Species 



Percent Frequency of Occurrence 



Grape spp. 
Ash spp. 
Silver maple 
Elm spp. 
Buttonbush 
Swamp privet 
Poison ivy 
Red mulberry 
Trumpet -creeper 
Greenbriar spp. 
Black willow 
Hackberry 
Cottonwood 
Basswood 



100 
75 
69 
63 
56 
56 
50 
44 
31 
25 
19 
19 
6 
6 



Area 7 in Figure 5-1. 

Data provided by Drs . Richard and Jean Graber, Illinois 
Natural History Survey. Sixteen plots .011 ha (.05 acre) 
every 0.8 ha (2 acres) were sampled. 



5-4( 



Vcjietation 



HERBACEOUS VEGETATION -- FORBS AND GRASSES 

Herbaceous vegetation forms the l°f^^/',^^^^ef whose 
hnttnmland forest. It consists of forbs and grasses wnose 
specie vary "th the season, soil and light conditions and 
floodinc Generally, the amount of ground cover is greater 

J^ar^af- where more'^unlight Penetrates the overs tory. Both 
flooding and shading appear to reduce 5^%""^^!" J^^^; i^^,. , 
Pnrh;; pivp likelv to be the least prevalent m the wiIIovn 
^^ottonwood'commLuy'because of tL delaying of estabish- 

ment by spring flooding. Areas of ^P^^^^J g^ate ?n?o 
are not uncommon if water levels remain high late into 
the growing season. Areas dominated by ^^^^ %f^^' '^^^^^^ 
ceous species are also not unusual. Klein et al. C1975. 
39r£ound that the ground cover in the silver -ape commu- 
nity was relatively sparse with a coverage of less than 
25b in most areas and often less than So. 

Some common herbs that we and others have noticed in 
the Illinois River bottomland forest are wood nettle 
(Laportea canadensis ), bur-cucumber (Sicvos a npulatus ) 
l izard ' s t ail ( Sau TTIrus cernuus ) , smartweedsnT^ygonum 
spp.), asters ( Aster spp.), beggar ticks (Bidens spp . ) , 
levelKced Cl mpiTT^s biflora) , and waterlFiTHlzdro- 
phvllum virglnianum ). A more complete listing of the 
forbs i n the project area is presented m Table ^-^ 
in the appendices. 

Grasses also occur in the Illinois ^^^^^ ,^°"?'"i^"?^„ 
Turner (1954: 770) noted that the landward sides of bottom 
land forest can merge into grass associations if no distur- 
bance occurs. Unfortunately, few of these sites exist 
along the Illinois River today. Tall slough or cord grass 
(Spartina michauxiana ) and panic grasses (Panicum spp. J 
occur fTiquently in the floodplain. A listing of the 
grasses likely to occur in the project area is presented 
in Table C-4 in the appendices. 

Effects of Diversion 

The water tolerances of herbaceous plants vary among 
species, but they appear to be more sensitive to high water 
conditions than shrubs and trees. Hall et al. (1946: 5bj 
found that relatively short periods of flooding during the 
growing season were injurious to terrestrial herbs. iney 
noted (1946: 55) that the perennating structures of terres- 
trial herbs can be killed if submerged for 30 days during 



5-47 



Vegetation 



the growing season and that some intolerant species died 
after 2 weeks of inundation. Kramer (1951: 731) believed 
that herbaceous species with the ability to quickly develop 
adventitious roots often showed the least injury to floodinj 
Kunshek (1971: 84) noted that velocity from high water 
levels is detrimental and can remove herbaceous vegetation. 
Undoubtedly, debris and silt deposited from high water 
levels also contribute to a reduction in the herb strata. 

Increased water levels via diversion would be detri- 
mental to the majority of the herbaceous and grass species 
existing in the floodplain if the water levels were 
increased during the growing season and inundation 
lasted 2 weeks or longer. Diversion during the non- 
growing season of herbaceous vegetation should have 
reduced detrimental effects except for those caused 
by deposition of silt and debris. 



WETLAND VEGETATION 



Various forms of wetland vegetation occur in the 
Illinois River valley. These plants occupy shallow 
water adjacent to the river, the margins and shores 
of bottomland lakes, aid low moist areas that are ex- 
posed during the growing season. Wetland vegetation 
provides food and habitat important to both wildlife 
a nd fish. 

Four major types of wetland vegetation occur in 
the Illinois River valley. (1) Emergent or marsh 
vegetation germinates and grows in water usually less 
than 31 cm (1 ft) deep. (2) Submergent vegetation 
grows on lake or river bottoms at maximum water depths 
of 1.2-1.5 m (4-5 ft) with some forms growing unattached 
or free-floating. (3) Floating aquatic plants grow 
anchored on lake or river bottoms at maximum depths of 
1.2-1.5 m (4-5 ft) with leaves that float on the surface. 
(4) Moist-soil vegetation volunteers and grows on mud flats 
exposed by low water during the summer. The following 
discussion includes the most common and important species 
of these four types of wetland vegetation that occur in 
the Illinois Valley. 



5-4fl 



Vegetation 

EMERGENT, SUBMERGENT, AND FLOATING AQUATICS 

Emergent Vegetation 

River Bulrush 

River bulrush C Scirpus fluviatus ) , a dominant marsh 
riant, is the most common emergent aquatic plant in the 
Illinois Valley. Its coarse, stiff, triangular stems 
usually reach heights of 1.2-1.8 m (4-6 ft). River 
bulrush is found on moist soil and in shallow, marsny 
areas at the edge of bottomland lakes. Peoria and La 




data) . 



River bulrush occurs on lakes with fluctuating vater 
levels (Hall et al., 1946: 40; Bellrose and Brovn, 1941: 
207: Weller and Fredrickson, 1973: 276). Bellrose and 
Brov-n (1941: 207) found optimum depth for river bulrush 
grovth in the Illinois River to be 0.34 to 0.5 m (12-18 mj . 

River bulrush was the most abundant aquatic plant 
species from 1938 to 1942 in bottomland lakes that fluc- 
tuate directly vith the Illinois River. However, it was 
proportionately more abundant in lakes where water levels 
were stabilized at an optimum level for aquatic and marsh 
plants (Bellrose et al ., 1979, inpress) . Although river bulrush 
is tolerant of fluctuating water levels, permanent in- _ 
creases have been found to be detrimental to it. The im- 
plementation of the 2.7-m (9-ft) navigation channel in_ 
1938 increased low water levels in Douglas Lake approxi- 
mately 0.6 m (2 ft). This increase resulted in the de- 
cline of river bulrush from 41 4 ha (1,023 acres) in 1940 to 
231.5 ha (572 acres) in 1959 and 199.1 ha (492 acres) m 
1976 (Bellrose et al., 1979, in press). 

River bulrush propagates largely by root stalks and 
tubers (Bellrose, 1941: 267). Only rarely does it pro- 
duce seed in the Illinois Valley, and then only in small 
patches (Bellrose, 1941: 266; Bellrose and Anderson, 1943: 
431). The seeds require moist soil for germination (Bell- 
rose, 1941: 277; Kadlec, 1960: 98). In spite of its poor 
seed production, river bulrush often competes successfully 
with more desirable waterfowl species (such as marsh 
smartweed) by virtue of its effective propagation and its 
tolerance of fluctuating water levels. 



5-49 
Vegetation 



River bulrush provides few seeds for v.'aterfowl to con- 
sume. However, it does provide brood habitat for nesting 
wood ducks and for the small number of mallards which nest 
in the Illinois Valley. Bellrose (1950: 314) found that 
muskrats selected river bulrush as their fourth most 
preferred food following cattails ( Typha sp.), pickerel- 
weed ( Pontederia cordata ) , and hard and soft stem bulrushes 
( Scirpus acutus , S. validus ) . Because these species of 
marsh plants now seldom occur in the Illinois River back- 
waters, river bulrush is probably the m.ost important food 
source for muskrats. Bellrose (1950: 307) also found that 
the highest muskrat house density during the 1940,'s 
occurred in beds of river bulrush. 

Marsh Smartweed 

Marsh smartweed (PoIv^oiudti coccineum) is the second most prevalent marsh 
plant in the Illinois Valley. Almost 30*o (625.7 ha, 1,546 
acres) of the total 2,086.2 ha (5,155 acres) of marsh 
in Peoria and La Grange pools is estimated to be marsh 
smartweed. 

Marsh smartweed is tolerant of fluctuating water levels 
(Bellrose, 1941: 275). Bellrose et al. (1979, in press) indicate 
that during the period of 1938-1942, marsh smartweed was 
the third m.ost abundant aquatic plant in lakes that 
fluctuated directly with the Illinois River. However, it 
was proportionately more abundant in lakes where water 
levels were stabilized at an optimum level for aquatic and 
marsh plants. The optimum depth at which marsh smartweed, 
like river bulrush, occurred in the Illinois River valley 
was 31 to 46 cm (12 to 18 inches) (Bellrose and Brown, 1941: 
207). The stems and foliage of the semi-erect marsh smart- 
weed plant float as the water rises, making it more toler- 
ant of floods than river bulrush. Thus, marsh smartweed 
often invades beds of river bulrush after flood waters have 
destroyed them (Bellrose, 1941: 54). This occurred at 
Rice Lake (La Grange Pool) when a dam constructed during 
1945 raised the water level 0.4 m (1.3 ft) and resulted 
in a reduction of river bulrush. However, an additional 
increase of 0.37 m (1.2 ft) during 1961 resulted in the de- 
cline of marsh smartweed. Like river bulrush although not 
to as great an extent, marsh smartweed can withstand severe 
wave action (Martin and Uhler, 1939: 122). 

Marsh smartweed propagates by rootstocks and seeds 
(Bellrose, 1941: 277; Martin and Uhler, 1939: 76). In the 
Illinois Valley, its seed production is very sporadic. 
Marsh smartweed m.ust be inundated to produce significant 
yields of seeds (Bellrose and Anderson, 1943: 427). 



Vegetation 



Beds of marsh smartwecd are especially attractive and 
valuable to migratory vaterfowl. They provide ideal cover 
for loafing and roosting as veil as highly palatable and 
nutritious seeds (when inundated). In addition, they supply 
brood habitat for breeding wood ducks and mallards. Marsh 
smartweed, although not as important as river bulrush, pro- 
vides food and housing material for muskrats. 

Cattail 

Common cattail ( Typha latifolia ), narrow- leaved cat- 
tail (T. angustifolia ) , and a hybrid of these two species 
(T. glavea ) occur in isolated areas along the shores of 
bottomland lakes in the Illinois Valley. Cattails covered 
hundreds of hectares just above the Starved Rock Lock and 
Dam during the early 1940's. Presently because of 
fluctuating water levels and sedimentation, cattails rarely 
occur in the Illinois River backwaters. 



Hall et al. (1946: 34) reported that common cattails 
sprouted and grew in water up to 0.6 m (2 ft) deep in 
Tennessee. Germination experiments in a greenhouse indi- 
cated that common cattails sprouted at depths up to 41 cm 
(16 in) but did better as the water became shallower with 
an optimum depth of 2.5 cm (1 in) (Weller, 1975: 385). 
Germination requirements for narrow-leaved and hybrid cat- 
tails are similar to that of common cattail (Bedish, 1967: 
295). When flooded, cattails propagate utilizing rhizome 
shoots (Weller, 1975: 397). 



McDonald (1955: 28), Kadlec (1960: 90) 
(1975: 385) indicated that common cattails 
water less than 0.3 m (1 ft) deep. In the 
valley, Bellrose and Brown (1941: 207) foun 
timum depth for comjr.on cattail ranged from 
m (6 to 24 in). McDonald (1955: 28) report 
Lake Erie marshes, narrow- leaved, hybrid, a 
tails did not generally grow in water deepe 
(3 ft), 0.61 m (2 ft), and 0.30 m (1 ft), r 
He also found that common and hybrid cattai 
access to air during the winter for surviva 
cattails did not. 



, and Weller 
grew best in 
Illinois River 
d that the op- 
0.15 to 0.61 
ed that in 
nd common cat- 
r than 0.91 m 
espectively . 
Is required 
1, but hybrid 



Although cattails occurred only in Starved Rock 
Pool (Upper Pools) from 1939 to 1945, cattails were the 
most preferred food of muskrats in the Illinois River bottom- 
land lakes (Bellrose, 1950: 314). Cattails also provide 
resting and rearing cover for waterfowl, bitterns, rails, 
and song birds . 



5-51 
Vegetation 

Duck Potato 

Dense beds of duck potato (Saj;ittaria calyci na and S. 
latifolia ) formerly occurred in "IjotTomiand lakes of the 
Illinois River. Changing conditions have now restricted 
duck potato to only a few areas. Duck potato is found in 
the Illinois River valley growing on mud flats, on the 
shoreline, and in shallow water averaging less than 0.3 m 
CI ft) deep (Bellrose, 1941: 275). Duck potato was most 
abundant in lakes that fluctuated directly with the 
Illinois River during the years of 1938-1943 (Bellrose et al., 
1979, in press). Yeager (1949: 49) found that duck 
potato was the only emergent plant to survive silt-laden 
flood waters during the growing seasons of 1943, 1944, and 
1945 at Calhoun Point (Alton Pool). 

Sag it tar ia Jati folia propagates via seeds and tubers 
whereas S. calycma utiHzes seeds only (Bellrose, 1941: 
277). TEe seeds aTe readily consumed by ducks; however, 
the deeply buried tubers of S. latifolia are occasionally 
consumed by canvasbacks and ring-necks (Bellrose and 
Anderson, 1945: 427). Duck potato is rated as a poor 
muskrat food. Muskrats consume mostly the stems of cattails 
but they will also ingest the roots and tubers (Bellrose, 
1950: 304). 

Marsh Mallow 

Marsh mallow ( Hibiscus mi li taris ) , easily identified 
by its large showy pink flowers, grows in moist-soil areas 
and in shallow waters along the edge of bottomland lakes. 
It reproduces from seeds which are discharged from cap- 
sules late in the growing season. Hall et al. (1946: 30) 
found that in the Tennessee Valley, dewatering was necessary 
for marsh mallow seeds to germinate but established plants 
were able to grow through at least 0.9 m (3 ft) of water. 
Marsh mallow was also reported growing with its roots 
submerged in the Tippecanoe River (Lindsey et al., 1961: 
15). Small patches of this plant are found primarily in 
moist-soil areas in the Illinois Valley that are first 
exposed by subsiding high water early in the spring. Al- 
though marsh mallow is not generally regarded as a 
waterfowl food plant, Bellrose and Anderson (1943: 430) 
found that a few seeds were consumed by waterfowl in the 
Illinois River valley. 



Vegetation 



Other Emergents 

In addition to the emergent marsh plants discussed above, 
several other less robust species were once abundant along 
the bottomland lakes of the Illinois River. Increased sedi- 
mentation has filled in the shallow areas that contained 
emergents (Bellrose et al., 1977: C-43). These areas now 
support moist-soil plants or black willow trees. SedimentatK 
has also created a soft bottom and has increased turbidity 
which prevents light from reaching the bottom. Both of 
these factors make it difficult for emergent plants to 
germinate. The following species now only rarely occur when 
specific conditions are satisified in bottomland lakes of 
the Illinois Valley: 

Pickerelwecd ( Pontederia cordata ) 

Hardstem bulrush ( Scirpus acutus ) i 

Softstem bulrush ( Scirpus validus ) i 

Wild rice (Z izania aquatical 

Giant bur- reed ( Sparganium eurycarpum ) 

Water primrose ( Jussiaea diffusa ) 



Submergent and Floating Aquatic Plants 



Several species of submergen 

plants once flourished in the 111 

the early 1960's, submergent plant 

of floating aquatic plants have v 

\ the river and bottomland lakes. 

turbiditY, the main factors respon 
have: (1) reduced the amount of 
synthesis; ('2') created a false or 
anchorage difficult or impossible 
productive areas of bottomland la 
had occupied. 



t and floating aquatic 
inois River valley. Sinc^e 
s and all but one species" 
irtually disappeared from 
Increased sedimentation and 
sible for this decline, 
light available for photo- 
soft bottom making root 
; and (3) filled shallow, 
kes which these plants 



Occasionally conditions exist that allow limited 
growth of the more tolerant submergent aquatic plants, such 
as sago pondweed ( Potamogeton pcctinatus ) , curlyleaf pond- 
weed (P. crispus ) , longleaf pondweed (P. nodosus ) , wild 
celery ( Vail isneria americana ) , and coontail ( Ceratophvllum 
demersum ) . These five species occurred in only a few 
places during the summer of 1978. American lotus 
(Nelumbo lutca ) , which grows in several bottomland lakes, is 
the only floating aquatic commonly found growing in the 
Illinois Valley. 



5-53 



Vegetation 



Sago Pondweed 

Sago pondweed, one of the most cosmopolitan submergent 
aquatics, propagates via seeds, tubers, and plant parts in 
the Illinois Valley (Bellrose, 1941: 277). Sago was noted 
growing in the Illinois River at two locations during the 
summer of 1978. The largest area was found at the conflu- 
ence of the Kankakee and Des Plaines rivers (Upper Pools) . 
Records indicate that this bed has existed since at least ^ 
1973. The second smaller area was on the east shore of 
the state-owned Woodford County Conservation Area (Peoria ""■ 
Pool) . This was the first time sago has been recorded ' 
growing at this location since the late 1950's (personal 
communication, Richard Brook, Illinois Department of Con- 
servation) . 






In a Manitob 
tween mid-May and 
and flowered in m 
mid-August to Sep 
a similar growing 
River during 1976 
that supported sa 
nificantly lower 
high soil organic 
tion; (3) shallow 
standing crop of 
to occur at water 
with sago occurri 
and a maximum of 
that the greatest 
River in Utah was 
Bellrose (1941: 2 
water over 1.4m 
Illinois River (L 
(1959: 159) found 
Chautauqua when t 
0.9 m (3 ft) . 



a marsh, sago pondweed growth began be- 
mid-June, and plants reached the surface 
id-July. Peak foliage was present from 
tember (Anderson, 1978: 155). We noted 
season on Pool 19 of the Mississippi 
Anderson (1978: 156) found sites 
go in the Manitoba marsh had: (1) sig- 
soil clay content, low bulk density, and 
matter; (2) less exposure to wave ac- 
water; and (4) low turbidity. The peak 
sago was found by Anderson (1978: 157) 
depths between 50-60 cm (1.6 -2.0 ft) 
ng in a minimum of 20 cm (8 in) of water 
95 cm (3.1 ft). Robel (1962: 222) found 
amount of sago in a marsh on the Bear 
in water depths of 38-46 cm (15-18 in). 
63) indicated that sago was absent in 
(56 in) deep in Lake Chautauqua on the 
a Grange Pool) . Jackson and Starrett 

the best growth of sago occurred in Lake 
he maximum depth of the lake was around 



Bellrose and Low (1944: 15) and Jackson and Starrett 
(1959: 157) noted that the best production of sago pond- 
weed occurred when the water depth remained stable diirinq 
the growing season. Bellrose et al.(1979, in press) reported 
that a water stability index calculated using eight years 
of data from Lake Chautauqua suggested that water stability 
accounted for approximately 301) of the yearly change in 
abundance of sago pondweed. Abundance of sago pondweed 
in the Illinois River from 1938-1943 was also greatest in 
lakes where water levels were stabilized at optimum levels 



5-5 



Vegetation 



for aquatic and inarsh plants. A rise in water levels of 
6-0 9 m (2-3 ft) destroyed most of the sago pondweed in 
Jack Lake on the Illinois River (La Grange Pool) (Bellrose, 
1941: 254). 

Bellrose (1941: 261) also found that as the water 
transparency in Illinois glacial lakes and the Illinois 
River increased, so did the depth and abundance of sago 
pondweed. McCombie and Wile (1971: 227) noted that the 
finely divided leaves in this species resist the accumu- 
lation of silt and thereby give it an advantage over broad- 
leaf species in flowing water. 

Sago pondweed was regarded as the most important single 
waterfowl food plant on the continent (Martin and Uhler, 
1939: 25). However, as a result of low seed yields and 
poor tuber production in the Illinois River valley, Bell- 
rose and Anderson (1943: 428) rated it as only a fair 
duck food. Currently sago pondweed only rarely occurs 
in the valley and is not considered a significant water- 
fowl food. 



Wild Celery 

Wild celery first occurred in the Illinois River at 
the confluence of the Des Plaines and Kankakee rivers 
(Upper Pools) and near Starved Rock Lock and Dam after the 
.ock and dam went into operation during 1938. In 1948 it 
^disappeared from these areas and did not reoccur in any 
abundance until 1978. Mills et al. (1966: 14) noted that 
the Peoria Lock and Dam stabilized low water levels in 
Upper Peoria Lake, resulting in a luxuriant growth of 
wild celery. This growth peaked in 1949, after which, 
except for a small gain in 1952 and 1953, it declined and 
disappeared from Upper Peoria Lake. 



Water depth for optimum growth of wild celery is 
between 0.3-1.5 m (12-60 in) (Martin and Uhler, 1939: 4 
Bellrose (1941: 249) indicated that wild celery preferr 
stable water levels in the Illinois River. Hunt (1963: 
365) and Chamberlain (1948: 352), studying wild celery 
the Detroit River in Michigan and in Back Bay, Virginia 
respectively, indicated that fluctuating water levels 
did not adversely affect this plant. The Illinois Rive 
differs from these areas in that its fluctuations are 
greater in magnitude and its waters are more turbid, a 
factor which limits plant growth. Sediment from tribut 
streams enters the Illinois River during water level fl 
tuations, further adding to turbidity which decreases t 
amount of light reaching aquatic plants. 



3). 
ed 



ary 
uc- 
he 



I 



5-55 



Vegetation 



Bellrose (1941: 261) found that an average transparency 
of less than 23 cm (9 in) throughout the growing season 
almost precludes development of submergent and floating 
aquatic plants in the Illinois River. Secchi disk readings 
taken at several locations in the channel of the Illinois 
River during September and October, 1978 (Table 5-20 ), 
substantiates Bellrose's findings. Starved Rock Lock and 
Dam, the only location with a transparency much greater 
than 23 cm (9 in) , was th e_only location to support \^>^ 
wild celery in 19787^ 

Wild celery propagates via winter buds and seeds in 
the Illinois River valley (Bellrose, 1941: 277). The winter 
buds are preferred foods of canvasback and ring-necked 
ducks. Record high populations of these ducks in the 
Illinois Valley from 1938 to 1978 occurred in Upper 
Peoria Lake during 1949, 1952, and 1953 -- the same years 
that wild celery production peaked in Upper Peoria Lake. 

Coontail 



Co on tail growth 
Bellrose (1941: 261) 
(La Grange Pool) wit 
(1 1 in) , scattered p 
up to 1.4 m (54 in) 
1.5m (60 in) , coont 
ft) deep. Kadlec (1 
water from 0.15 to 1 
depth being 0.55 m ( 
amount of coontail i 
Beebe Lake (La Grang 
dropped from 0.76 m 
transparency remaine 
(Bellrose, 1941: 263 
0.46 m (1.5 ft) at A 
0.46 m (1 .5 ft) in 1 
by 1965. Stable wat 
Illinois Valley incr 
tail (Bellrose and B 
1944: 16). Bellrose 
the greatest concent 
Valley from 1938 to 
in which water level 
for aquatic and mars 



is also regulate 
noted that in ar 
h Secchi disk rea 
atches of coontai 
deep. Where the 
ail formed a dens 
960: 89) found th 
. 1 m deep (6-45 i 
16 in) in Backus 
ncreased by 155 h 
e Pool) when the 
(30 in) to 0.56 m 
d the same for 2 
) . After the wat 
nderson Lake in 1 
964, coontail vir 
er levels in bott 
eased production 
rown, 1941: 207; 

et al. (1979, in 
rations of coontai 
1943 were found i 
s were stabilized 
h plants. 



d by water transparency 
eas of Lake Chautauqua 
dings of 27.9 cm 
1 occurred in water 
Secchi readings were 
e mat 1.5-1.8 m (5-6 
at coontail grew in 
n) with the average 
Lake, Michigan. The 
a (384 acres) at 
average water depth 

(22 in) while the 
consecutive years 
er level was raised 
958 and an additional 
tually disappeared 
omland lakes of the 
and yields of coon- 
Low and Bellrose, 

press) found that 
1 in the Illinois 
n bottomland lakes 

at optimum depths 



Coontail was observed growing in the lower section of 
Spring Lake (La Grange Pool) during the summer of 1978 
when the water level was lowered to an average depth of 0.6 
m (2 ft). At this depth, sunlight was able to reach the 
bottom and enable coontail to develop. 



^ ui c; 7n Sccchi Disk Readings taken at Various Locations 
Table 5-20. Secchi Dis.^^.^ .^.^^^ Channel. September- 

October, 1978. 



Locati on 

Area 

Grafton 

Bath 

Spoon River mouth 

Henry 



Secchi Disk Readin 





River Mile 
2.5 


Cm 


incnes 




23.0 


9.1 




111.0 


18.0 


7.1 




120.5 


10.0 


3.9 




195.5 


23.5 


9.3 


md Dam 


232.0 


39.0 


15.4 



5-57 



Vegetation 



Coontail reproduces vegetatively , particularly by the 
bushy tips of the plant (Martin and Uhler, 19 39: 82; Bell- 
rose, 1941: 277). Since coontail rarely occurs in the 
Illinois Valley at the present time, seeds are probably 
the most important means of propagation. 

Coontail was classified by Bellrose and Anderson 
(1943: 425) as an excellent waterfowl food. It furnished 
little seed, but ducks make extensive use of the leaves 
and stems. Because coontail now rarely occurs in the 
Illinois Valley, it no longer is an important waterfowl food. 

Curlyleaf Pondweed 

Curlyleaf pondweed is a naturalized species that is 
native to Europe (Mohlenbrook, 1975: 88). McCombie and 
Wile (1971: 227, 228) found that this species tolerates 
waters highly enriched by urban wastes and occurs even 
in the most turbid lakes near Toronto, Canada. 

Curlyleaf was found growing in large beds just north {/^ 
of Starved Rock Lock and Dam and in Spring Lake during the 
summer of 1978. Its presence, like that of wild celery, 
was primarily a result of increased water transparency in 
the Starved Rock Pool (Upper Pools) and the combination of 
a lower lake level and increased transparency at Spring 
Lake (La Grange Pool) . 

Hall et al, (1946: 27) noted that curlyleaf rarely 
flowers and fruits in the Tennessee Valley but does so 
freely in New York State. Curlyleaf occasionally fruits 
in the Illinois Valley. However, the leafy parts of the 
plant and the associated invertebrates it harbors provided 
food for migrating waterfowl at Spring Lake during the 
fall of 1978, particularly wood ducks and green-winged 
teal. Curlyleaf propagates primarily by winter buds 
(Britton and Brown, 1970: 81; Grey, 1908: 75). These 
winter buds are rarely consumed by waterfowl. 

Longleaf Pondweed 

Longleaf pondweed was noted by Anderson (1959: 332) as 
occurring in nearly all bottomland lakes in the Illinois 
Valley. However, during this study longleaf pondweed ^^y/ 
was observed only at the Sanganois Conservation Area 
(Mas^on County, La Grange Pool). 

Low and Bellrose (1944: 12, 15) found that longleaf 
pondweed produced more seed (144 cc/m^) than other floating 
and submergent aquatic plants in the Illinois Valley. They 



5-5f 
Vegetation 

also noted that longleaf pondweed produced .ore -ed in lakes_ 
";';;/^rs"bni"ena r nduJois/llth^ough longleaf 

seeds less accessible to dabbling ducks than those of 
other marsh plants. 

Martin and Uhler (1939: 30) reported that longleaf 
nnndweed erew at depths of 0.9-1.5 m (3-5 ftj . beiirose 
?194 lei) found that in Lake Chautauqua (Mason County, 

[a Grange Pool), turbidity '''^'i^''U^)".^^7Zl Martin 
innpleaf Dondweed in water over 1 m (3 ft) deep. Martin 
an3^iMer^(1939? 30) also found that longleaf pondweed 
survived complete emergence on moist shorelines and with- 
Itood severe flooding better than other pondweeds . 

American Lotus 

American lotus, a floating aquatic plant, is the most 
abundant of the submergent and floating aq;;;^^^^ P J^^J^ 
remaining in the valley. It is found in small beds in 
several bottomland lakes from the Big Bend at Hennepin 
CFeoria Pool) to the confluence of the Mississippi and 
Illinois rivers at Grafton (Alton Pool). The large 
leaves of this plant either grow above the water on 
erect petioles or float on the water's surface. 

Bellrose and Brown (1941: 207) found ^^^^P^i'T^,;!^^^^ 
depth for the growth of lotus to be 0.5 to 1.0 m (18-40 m) . 
However, Hall et al. (1946: 34) reported lotus gi;°;;i^g 
to the surface in 2.4 m (8 ft) of water m the Tennessee 
Valley. This species is also tolerant of fluctuating 
water levels. Bellrose (1941: 254) reported that an 
increase of water levels from 0.6 to 0.9 m (2 to 3 tt) m 
mid-May during 1938 had no effect on lotus m the Illinois 
Valley. However, after a permanent increase at Anderson 
Lake (La Grange Pool) of 0.5 m (1.5 ft) in 1958 and an addi- 
tional 0.5 m (1.5 ft) in 1964, lotus disappeared (Bellrose 
et al . , 1979, in press) . ■ 

Lotus survived several years of high water in a 
Michigan marsh on Lake Erie (McDonald, 1955: 31). Hail 
et al. (1946: 42) found that in the Tennessee Valley, beds 
of lotus were destroyed when flooded to a depth greater 
than the length of their petioles for two weeks. The 



I 



5-59 
Vegetation 



increased water levels either snapped the leaf blades from 
the petioles or destroyed the leaves. The subterranean 
rootstock of the lotus was also found to be adversely 
affected . 

American lotus propagates by seeds borne on showy 
yellow flowers or by rootstocks (Bellrose, 1941: 277). 
This floating aquatic was found to be a poor duck food 
by Bellrose and Anderson (1943: 430). The hard, nutlike 
seeds are unpalatable to migrating ducks in the fall. 
However, wood ducks feed on them extensively in late 
August and early September before the seeds fully ripen. 
Lotus is a minor food source for muskrats in the Illinois 
Valley. 

As previously mentioned, several species of sub- 
mergent and floating aquatic plants occurred in the 
Illinois Valley. The environment of the river valley 
has been drastically altered by man's activities and 
most of the following species are now rare: 

Submergent \^ 

Bushy pondweed (naiad) ( Na j as guadalupens is ) 
Horned pondweed ( Zannichelliapalustris ) 
Leafy pondweed ( Potamo geton f oliosus ) 
Mud plantain ( Heteranthera d ub i a ) 
Small pondweed ( Potamogeton pusi llus ) 

F loating Aquatic 

White water lily i^i^ymphaea^ tuberosa ) 
Yellow pond lily ( Nymphaea advena ) 
Pickerelweed (Pontederia cordata) 



The Effects of Increased Diversion 
on Emergent, Submergent, and Floating Aquatic Plants 

The implementation of the 2.7-m (9-ft) navigation 
channel during 1938 raised water levels 0.76 m (2.5 ft) 
and 0.61 m (2 ft) over low flow levels at the southern ends 
of Peoria and La Grange pools, respectively (Bellrose et 
al., 1977: C-43). The rise in water levels reduced the 
exposure of mud flats during the summer months and in- 
creased water stability in the lower reaches of the 
pools. Habitat conditions were temporarily improved for 
aquatic and marsh plants. Conditions continued to be 
favorable for these plants at certain lakes in the 



Vegetation 



5-61 



^■1 ^Vo p;qrlv lQ60's As a result of 
C-39) . 



f Be 

(primar 
increas 
intensi 
has res 
increas 
River v 
sheet e 
constru 
sedimen 
of the 
suspend 
for inc 
disturb 
This tu 
decline 
plants 



tween 1945 a 
i ly corn and 
ed' by tD'o (B 
ve row-cropp 
ulted in wid 
ed the turbi 
alley. Coup 
rosion from 
ction of the 
tation probl 
current, thu 
ed sediment, 
reased barge 
ing bottom s 
rbidity and 

of emergent 
from the 111 



nd 1976, 
soybean 
ellrose 
ing on I 
esp read 
dity and 
led with 
changing 
nine- f o 
em by: 
s reduci 
and (2) 
traffic 
ediments 
sediment 
, submer 
inois Ri 



land plante 
s) in the II 
et al., 1979 
llinois Rive 
sheet erosi 
sedimentati 
the tremend 
agricultura 
ot channel c 
(1) the dams 
ng the river 
the navigat 
which incre 
(Bellrose e 
ation has re 
gent, and fl 
ver valley. 



d to row crops 
linois River basin , 
, in press) . This 
r watershed lands 
on and thus greatly 
on in the Illinois 
ous increase of 
1 practices, the 
ontributed to the 
slowing the speed 
's ability to carry 
ion channel allowed 
ased turbidity by 
t al., 1977: C-39). 
suited in the severe 
oating aquatic 



d pi 
t fr 
the 
fill 
ion 
n ha 
igin 
quat 
se p 
tion 
oria 
f mu 
f th 
d fl 



ant growth 
om reaching 
se plants c 
ed shallow 
(Bellrose e 
s created a 
al firm sub 
ic plants t 
lants are e 
However, 
Pool now c 
d flats tha 
e 2.7-m (9- 
ats have in 



Turbidity has limite 

ley by inhibiting sunligh 

plants. Without sunlight 

grow. Sedimentation has 

supported aquatic vegetat 

In addition, sedimentatio 

bottom that covers the or 

difficult for marsh and a 

foothold. Therefore, the 

wave and rough fish agita 

recreating mud flats. Pe 

mately the same acreage o 

before the construction o 

whereas La Grange Pool mu 

1,011.7 ha (2,500 acres) . 

In order to determine the effects of increased diversio 
on emergent, submergent, and floating aquatic Pl^jj^l^^f ^' 
level increases as a result of the 6,600- and 10,000 cts 
diversion were calculated for the 30 ^pril-l October 
growing season. This was accomplished by calculating the 
predicted average water level increases fjj^^^if ^l^^^'J-f . 
season from a computer model provided by the Chicago uii> 
trict Army Corps of Engineers. These increases were 
calculated for three years of dissimilar water conditions. 



in the Illi 
photosynth 
annot germi 
areas that 
t al., 1977 

soft flocc 
strate, mak 
o gain or r 
asily uproo 

sedimentat 
ontains app 
t were pres 
ft) channel 
creased by 



no is Val- 
esizing 
nate or 
formerly 
: C-43). 
ulent 
ing it 
etain a 
ted by 
ion is 
roxi- 
ent 



about 



5-61 



Vegetation 



1971, 1973, and 1977. 
culated for one refere 
as the reference point 
Grange Pool. These re 
they are located near 
pools, and thus reflec 
these pools. The wate 
the computer model wer 
for the 50 April-1 Oct 
daily river gauge read 
the U.S. Weather Servi 
in msl for the 6,600- 
would have occurred at 
and 1977 are shown in 
increases in relation 
(see Chapter 4 ) in P 
determine the effects 
submergent, and floati 



Increases in water levels were cal- 
nce point in each pool. Henry was used 

in Peoria Pool and Havana in La 
ference points were chosen because 
the middle of the Peoria and La Grange 
t the changes in the water levels of 
r level increases determined from 
e added to the average gauge readings 
ober growing season calculated from 
ings at Henry and Havana recorded by 
ce. The projected water level increases 
and the 10,000-cfs diversion that 

Henry and Havana during 1971, 1973, 
Table 5-18 . The projected water level 
to the elevation of the tree line 
eoria and La Grange pools were used to 
of increased diversion on emergent, 
ng aquatic plants. 



The distance between low water and the 
La Grange Pool is 1.23 m (4.0 ft), whereas 
is only 0.34 m (1.1 ft) in Peoria Pool (Tab 
The larger difference between the tree line 
La Grange Pool is possibly a result of two 
river falls at a faster rate in the La Gran 
in the Peoria Pool and greater fluctuations 
La Grange Pool as a result of three main tr 
(Mackinaw, Spoon, and La Moine) that empty 
tance between low water levels and the tree 
and La Grange pools determines the increase 
needed to inundate all of the mud flats in 
the water levels are at the tree line, the 
of hectares are available for aquatic plant 
the lake basins. If water levels are raise 
line, bottomland timber begins to flood. P 
tion would eventually kill bottomland timbe 
potentially creating shallow areas availabl 
plant growth. 



tree line in the 
the difference 
le 5-21) . 

and low water in 
factors. The 
ge Pool than 

occur in the 
ibutary rivers 
into it. The dis- 

line in Peoria 

in water levels 
each pool . When 
maximum number 

growth within 
d above the tree 
ermanent inunda- 
r (see page 5- 38) 
e for aquatic 



Average gauge readings during 1971 and 1977 at Henry 
(Peoria Pool) for the 30 April-1 October growing season were 
less than 0.30 m (1 ft) below the tree line elevation of 
441.6 ft (msl) (Table 5-18). During 1973, a year with 
high water levels, the average gauge reading for this 
growing season was over 0.61 m (2 ft) higher than the 
tree line (Table 5-18 ). The 6,600-cfs diversion would 
have raised the water levels to 0.27 m (0.9 ft), 1.13 m 
(3.7 ft), and 0.43 m (1.4 ft) above the tree line during 
1971, 1973, and 1977, respectively (Table 5-18 ). The 



5-62 



o -a X 




O O 4-" 




U, -H 




1 i^ oc 




tn fl; r~- 




• D- cn 




C '— 




M 




■w C O 




- •-( ^-J 




> 




C« O CTi 




■M J- K) 




re (J) cn 




t— 1 1— 




U- QJ 




JZ E 




TD +-I O 




:3 (- 




^ ^, t+H 




o 




<-H l-l-l W 




O (- 




w re 




,— V.-I (L> 




t« o >- 




0) o 




^- D. t+-( 




u o 




< 0) 




^— ' M ■*-> 




C C 




c/i re <D 




OJ ^H U 




!- U !-H 




re (u 




+-< re a, 




O J 




o a; 




n: -13 j= 




c +-» 




1+-I re 




O T3 




re c 


. 


^-i -H re "XJ 


<D u 


(1) 


^ o u 


!/) 


E a» (u 


o 


D D- Xi 


D- 


2: o 


X 


0) +J 


QJ 


(U x u 




*J -t-i G 


tfl 


re 


re 


e c ^ 


5 


*pH •—1 




X o 


1— 1 


O U1 4-1 


(L) 


>H r-l 


> 


p. re X o 


p. > ^ 


J 


< s- 3 




O "-3 X 


(U -M 


U 


J= c o 


re 


H '-"- 


w 




CO 





,— V 






in 











o 


(-. 


t/5 


> 


u 


4-> 


•rH 


< 


re 


4-1 


V— > 


1— ( 


re 

I— ( 


C/1 


Uh 


3 


<b -al 


E 


J-. 


3 


3 


re 


»- 


u 


■t-j 




u 


U 14h| 


< 




°l 



5-63 
Vegetation 



10,000-cfs would have increased the water levels 0.70 m 
(2.3 ft) above the tree line during 1971 and 1977 (Table 5-18). 
As a result of high river levels, a 10,000-cfs diversion 
would not have occurred in 1973. 

Average gauge readings at Havana (La Grange Pool) for 
the 30 April- 1 October growing season without increased 
diversion were 1.04 m (3.4 ft) and 0.55 m (1.8 ft) below 
the tree line elevation of 434.4 ft (msl) during 1971 and 
1973, respectively (Table 5-18). During 1973 water levels 
were 0.64 m (2.1 ft) above the tree line. Increased water 
levels during the 30 April-1 October growing season as a 
result of the 6,600-cfs diversion would have been 0.49 m 
(1.6 ft) and 0.06 m (0.2 ft) below the tree line during 
1971 and 1977, respectively, and 1.10 m (3.6 ft) above the 
tree line during 1973 (Table 5-18 ). The 10,000-cfs diversion 
would have resulted in the average gauge readings being 
0.15 m (0.5 ft) below the tree line during 1971 and 0.12 
m (0.4 ft) above the tree line during 1977. A 10,000-cfs 
diversion would not have been achieved during 1973. 

During the three study years in the Peoria Pool, the 
6,600- and 10,000-cfs diversion would have resulted in a 
minimum raise in water levels of 0.27 m (0.9 ft) above the 
tree line. Increases of this magnitude would have resulted 
in water levels too deep for the growth of submergent, 
emergent, and floating aquatic plants in most of the lake 
basins. New shallow areas for wetland plant growth would 
eventually become available as bottomland timber began to 
die. 

In the La Grange Pool, increased diversion would not 
have raised water levels as high above the tree line. This 
is a result of the larger difference in elevation between 
the tree line and low water levels in this pool as compared 
to Peoria Pool. The 6,600-cfs diversion in La Grange Pool 
would not have raised water levels above the tree line during 
1971 and 1977. The 10,000-cfs diversion would not have 
raised water levels above the tree line during 1971. In- 
creased diversion during these years, however, may still 
have inundated additional shallow areas that could be 
available for aquatic plant growth. 

As a result of the turbid water and soft flocculent 
bottom, any new shallow areas created around bottomland lakes 
by increased diversion may not, in most cases, support aquatic 
plant growth. Firm substrate in flooded bottomland timber 
could possibly support emergent vegetation until the bottom 
became too flocculent from sedimentation for these plants 
to remain rooted. 



5-6' 



Vegetation 





River Bulrush 

The 6 600-cfs diversion would have raised water levels 
from 0.49 to 0.52 m (1.4 ft to 1.7 ft) in P^or ia^Pool and^ 

0.48 

1971, 

have 

in La Grange^'Pool for the same time period (Table 5-18 ). 
Bellrose et al. (1979, in press) noted that a 61-m 
(2-ft) increase in water levels during 1938 at Douglas 
Lake in Peoria County on the Illinois River at first 
resulted in a slight increase in river bulrush. However, 
by 1940 the area covered by river bulrush declined by 
41. To. 'increased diversion would result in deeper water 
levels at the tree line in Peoria Pool (Table 5-18). 
Therefore, river bulrush would be inundated to a greater 
depth in Peoria Pool, thereby sustaining a larger loss than 
in the La Grange Pool. New beds of river bulrush would 
probably appear as flooded bottomland timber began to die 
and expose new shallow areas with a firm bottom. 

Marsh Smartweed 

Marsh smartweed would initially benefit from deeper 
water as a result of increased diversion. Bellroseet al. 
(1979, in press) found that when water levels were in- 
creased at several bottomland lakes in the Illinois Valley, 
marsh smartweed invaded areas previously occupied by 
river bulrush but ultimately declined when water levels 
continued to remain high. Martin and Uhler (1939: 76) 
noted that when marsh smartweed is flooded by shallow 
water it fruits abundantly; but if it remains growing con- 
tinuously in water for more than 2 years, there is usually 
a decline in abundance of plants and also production of 
seeds. Marsh smartweed would undoubtedly reestablish itseii 
along the margins of the waters edge and in new areas as 
bottomland timber died. 

Duck Potato 

Duck potato occupies mud flats with waterlogged soil 
or marginal areas along the tree line of bottomland lakes 
where the bottom is either sandy or firm. Duck potato 



5-65 
Vegetation 



is found growing in shallow water averaging less than 0.30 m 
(1 ft) deep in the Illinois River (Bellrose et al., 1979, 
in press). Increased diversion would inundate most areas 
that harbor duck potato to a depth that would be detrimental 
to this plant. However, duck potato would probably inhabit 
new areas created as high water killed bottomland timber 
(Yeager, 1949: 46). After several years, these areas would 
fill with sediment and result in the bottom being too 
soft for duck potato to gain or maintain root anchorage. 

Cat tai Is 

As a result of fluctuating water levels, cattails 
have never been abundant in the Illinois River valley. 
However, common, narrow- leaved, and hybrid cattails occupy 
shallow areas directly above the navigation dams where water 
level fluctuations are minimized. In the Illinois River 
valley, Bellrose and Brown (1941: 207) found the optimum 
depth for common cattail to range from 0.15 to 0.61 m (6 to 
24 in). Increased diversion would inundate most areas 
that cattails occupy to a depth that would result in mor- 
tality. New shallow areas created by the death of bottom- 
land timber from inundation would probably be pioneered 
by cattails (Yeager, 1949: 54). However sedimentation 
would eventually fill these newly created areas, thus 
choking out the cattails. 

Submergent and Floating Aquatic Plants 

Few submergent and floating aquatic plants exist in the 
Illinois River valley today. The growth of submergent and 
floating aquatic plants in the Illinois River valley is 
primarily determined by the amount of turbidity in the 
water of bottomland lakes during the growing season (see 
pages 5-55 fi 5-56 ). Increased diversion would create new 
shallow areas that would be potential habitat for submer- 
gent and floating aquatic plants. However, turbidity 
caused by the resuspension of the soft flocculcnt bottom 
by wave and rough fish agitation would preclude the develop- 
ment of submergent and floating aquatic plants in these 
new areas. Increased water levels would also have a 
detrimental effect on existing submergent and floating 
aquatic plants. As the water depth became deeper, the 
amount of sunlight reaching these plants would be diminished, 
thereby inhibiting growth and germination. 



5-66 
Vegetation 

MOIST-SOIL PLANTS 
Folloving high water levels resulting from the spring 

mud nats'in the bottomland lakes. Soil moisture and 
tempera ure conditions and oxygen tension vary on the mud 
fla?s in accordance with the length of exposure to air and 
sunlight. As these soil conditions change, the germina- 
tion Requirements of different plant species are satisfied 
and thus moist-soil plants appear in ^ands or zones stretch- 
ing backwards from the shorelines of mud flats toward the 
tree line. 

Rice and Spring lakes (Figure 5-2 ) were selected as 
study areas to examine the plant communities on mud 
flats in the Illinois Valley during late summer 1978. 
These lakes are owned and managed by the Illinois Depart- 
ment of Conservation and are protected from ^^^'J^, J^l Lels 
fluctuations by levees or control structures. Kater levels 
at these lakes are regulated by control structures that 
enable site managers to draw down water levels and expose 
mud flats during the growing season. 

Spring Lake 

Spring Lake is divided into two sections by a cross 
levee near the middle of the lake. This levee enables inde- 
pendent manipulation of water levels in each section ot the 
lake. A drawdown in the southernmost section of the lake 
began during the second week of March, 1978. A drop from 
132.0 m (433.0 ft) msl to approximately 130.9 m (429. b ttj 
msl was reached by the second week of September. However, 
by the first week of June, a 0.76-m (2.S-ft) drop m 
water levels had exposed most of the mud flats. ^^^^ 
vegetative sampling transects averaging 844.3 m (923.3 ydsj 
in length were established in areas of the mud flats that 
differed in time of exposure and, therefore, soil moisture. 

Transect 1, closest to the water or the lowest, was 
exposed by mid-June. This was the last of the transects to 
be dewatered. Transect 2 was divided into three distinct 
zones. The largest zone was exposed by drawdown in early 
May. The other two zones were exposed by mid-May and mid- 
June. Transect 3 was exposed by mid-May, one of the first 



5-67 



LAKE MICHIGAN 




ST. LOUIS 



25 50 

HILES 



50 

KILOMETERS 



Figure 5-2. Moist-soil plant study areas at Rice and 
Spring lakes. 



5-6 



Vcgetat i on 



to be dcwatered at Spring Lake. However, as a result of 
spring-ivater seepage on this transect, a marshy condition 
persisted throughout the summer. Most of transect 4 was 
located on an old levee that had been inundated when lake 
levels were increased during the 1950's. This section of 
the transect is higher than most of the lake bottom and was 
exposed by drawdown by the beginning of May. A small sec- 
tion of transect 4 was exposed in June. Most of transect 
5, the farthest from the water or the highest, was exposed ■ 
by the beginning of June. However, intermi ttent wet areas 
probably remained until the end of July. 

Rice Lake 

A drawdown to 132.6 m (435.0 ft) msl at Rice Lake 
(0.61 m (2 ft] below pool stage) was not achieved until 
August 15 because of high river levels that impeded water 
flow from the lake. Two study areas, one on the northern 
end and the other on the southern end, were selected for 
moist-soil food plants. Utilizing a transit, three 304. 8-m 
(333.3-yd) transects were established on the shoreline at 
each study area. These transects were set 10.2 cm, 25.4 cm, 
and 40.6 cm (4 in, 10 in, and 16 in, respectively) above and 
parallel to the water line. The transect 10.2 cm (4 in) 
above the water line is designated as transect 1 (the lowest 
transect) throughout this report; the transect 25.4 cm 
(10 in) above the water line is transect 2 (the middle 
transect); the transect 40.6 cm (16 in) above the water line 
is transect 3 (the highest transect). The suffixes N and S 
are used to differentiate between the northern and southern 
study areas. The date and length of time that each transect 
was exposed when sampled are presented in Table 5-22. 

In addition, soil moisture was determined with a 
soil moisture probe for each transect at Rice Lake by 
averaging readings taken at every other plot. Table 5-22 
also lists the average soil moisture reading in centibars 
of soil suction for each transect (0 centibars of soil suc- 
tion = total saturation of the soil). Transect 3N was 
measured following two days of rain and a subsequent 25.4-cni 
(10-in) increase in the lake level. Therefore, the soil 
moisture reading at 3N is unusually low, but realistically 
it should depict the relationship exhibited by the 3S 
transect . 



The percent canopy coverage (Daubenmire, 1959: 50-51) 
and the average height were tabulated for plant species 
that occurred in a l-m'^ (3.3-ft2) plot at 15.2-m (50-ft) 
intervals along each transect at Spring and Rice lakes. The 



5-69 



Table 5-22. Drawdown Date, Length of Exposure, and Soil 

Moisture of the Vegetative Sampling Transects 
at Two Rice Lake Study Areas. 



South Study Area North Study Area 

Transect # IS 2S 3S IN 2N 3N 



Drawdown 
Date 



8/15/78 8/8/78 8/1/78 8/15/78 8/8/78 8/1/71 



Length of 

Exposure 

in Days at 30 37 44 31 38 49 

Sampling 



Soil 

Moisture 

(Soil Sue- 0.39 18.69 0.72 0.22 

tion in 

Centibars) 



5-7(^ 
Vegetation j 



percent occurrence, average percent coverage, and average 
height were calculated for all species at each lake (Tables 
5-25, 5-24). 



'i 



Teal Grass (Eragrostis) ; 

Teal or love grass ( Eragrostis hypnoides ) was reported ' ! 
by Mohlenbrock (1975: 129) as occurring on wet ground, ' 
usually in sandy or muddy areas throughout the state of 
111 inois . 

Teal grass covered an average of li.bl of and occurred 
on 14.01- of the sample plots on tlie transects at Spring Lake (Tale 
At Rice Lake, teal grass ranked 5rd in both average percent ;■ 
coverage (24.81.) and occurrence (931.) (Table 5-25). 

[ 

Transect 1, the last to be exposed at Spring Lake, had 
the greatest average percent coverage and occurrence of ; 
teal grass (Table 5-26). This transect was exposed by ' 

drawdown near mid-June. Teal grass also occupied wet areas 
on transect 2 that were exposed at approximately the same 
time as transect 1 (Table 5-26) . On both transects 1 and 2 
at Spring Lake, teal grass was an understory of the much , 
larger red-rooted nutgrass. Teal grass was one of the 
most abundant plants at Rice Lake (Table 5-23), The transects 
at Rice Lake were exposed late in the growing season during 
August . 

These data indicate that teal grass becomes established 
on mud flats that are exposed late during the summer growing 
season. Neither soil moisture nor the length of time mud 
flats were exposed was related to the percent coverage of 
teal grass (Table 5-24). Possibly plant competition was 
responsible for the variation in the percent coverage that 
existed at the north and south study areas at Rice Lake. 

Teal grass was ranked by Bellrose and Anderson (1943: 
432) as the eighth most important duck food in the Illinois 
River valley. However, giant bur-reed and coontail, ranked 
as the sixth and seventh most important duck food plants, no 
longer are common in the Illinois River valley. Therefore, 
teal grass should currently be ranked as the sixth most im- 
portant duck food plant. Low and Bellrose (1944i 13) found 
that teal grass produced an average of 46.0 cc/m of seeds 
in the Illinois River valley. It was the second most pro- 
ductive duck food plant in lakes with semistable water levels 
in the Illinois River valley. Bellrose (1941: 275) indi- 
cated that teal grass is tolerant of water-level fluctuations, 



5-71 



Table 5-23. Percent Occurrence and Average Percent Coverage of 
Moist-Soil Plants at Rice Lake, September 1978. 



Species 

Pigweed ( Acnida sp.) 

Chufa ( Cyperus esculentus ) 

Teal grass ( Eragros tis hypnoides ) 

Japanese millet ( Echinochloa f rumentacea ) 

Arrowhead ( Sagittaria calycina ) 

Beggar-ticks ( Bidens sp.) 

Awned cyperus ( Cyperus inf lexus ) 

Cocklebur ( Xanthium sp.) 

Buttonbush ( Cephalanthus occidentalis ) 

Nodding smartweed ( Polygonum lapthi folium ) 

Cottonwood ( Populus deltoides ) 

Walter's millet ( Echinochloa walteri ) 

Black willow ( Salix nigra ) 

Rice cutgrass ( Leersia oryzoides ) 

Spike rush ( Eleocharis smallii ) 

Monkey- flower ( Mimulus ringens ) 

Long- leaved ammannia ( Ammannia coccina ) 

River bulrush ( Scirpus f luviati lis ) 

Duck millet ( Echinochloa crusgal li ) 

Marsh smartweed ( Polygonum muhlenbergii ) 

Small white morning-glory ( Ipomoea lacunosa ) 

Marsh mallow ( Hibiscus mi li taris ) 

Sugar maple ( Acer saccharum ) 

Creeping water primrose ( Jussiaea repens ) 

Straw- colored nutgrass ( Cyperus s tr i gosus ) 

Large- seed smartweed ( Polygonum pennsylvanicum ) 



Average 
Coverage 




Occur- 
rence 


26.5 


100.0 


25.2 


97.0 


24.8 


93.0 


10.3 


66.0 


10.1 


36.0 


6.7 


61 .0 


5.7 


24.0 


4.0 


29.0 


3.1 


19.0 


2.8 


48.0 


1 .6 


36.0 


1 .2 


19.0 


0.9 


15.0 


0.9 


23.0 


0.8 


4.0 


0.8 


30.0 


0.7 


25.0 


0.6 


5.0 


0.3 


8.0 


0.3 


1 .0 


0.2 


2.0 


0.2 


2.0 


0.1 


2.0 


trace 


2.0 


trace 


1 .0 


trace 


1 .0 



Table 5-24. Percent Occurrence and Average Percent Coverage I 
of Moist-Soil Plants at Spring Lake, September 197^ 



Average 



Speci es 

Red-rooted nutgrass ( Cyperus ery throrhi zos ) 

Beggar-ticks ( Bidens sp.) 

Largesccd smartuced ( Polygonum pennsy Ivanicum ) 

Duck potato ( Sagittaria latifolia ) 

Nodding smartweed ( Polygonum lapthi f ol ium ) 

Teal grass ( Eragrostis hypnoides ) 

Japanese millet ( Echinochloa frumentacea ) 

Duckweed ( Lemna minor ) 

Spike rush ( Eleocharis smallii ) 

Rice cutgrass ( Leersia oryzoides ) 

Small white morning glory ( Ipomoea lacunosa ) 

Jewelweed ( Impat iens bi flora ) 

River bulrush (Sc irpU s fluviatilis ) 

Narrow- leaved cattail ( Typha angustif olia ) 

Black willow ( Salix nigra ) 

Roundstem bulrush ^ Sci rpus validus ) 

Swamp loosestrife ( Decodon vert i ci 1 latus ) 

Velvet- leaf ( Abutilon t heophrasti ) 

Swamp smartweFd ( Polygonum hydropiperoides ) 

Tickle grass ( Panicum capi 1 lare ) 

Cottonwood ( Populus deltoides ) 

Creepin" water primrose ( Juss iaea repens ) 

Lady's thumb (P olygonum persicaria" ) 

Fog-fruit ( Lippia lanceolata ) 

Water locust ( Gleditsia aquatica ) 

Pigweed ( Acnida sp . ) 

Ivy-leaved morning-glory ( Ipomoea hederacea ) 

Shining cyperus ( Cyperus rivularis ) 

Wild rice ( Z izania aquatica ) 

Foxtail ( Alopecurus sp.) 

Dodder ( Cu scuta sp.) 

Duck millet ( Echinochloa crusgalli ) 

Long-leaved ammannia ( Ammannia coccina ) 

Straw-colored nutgrass ( Cyperus strigosus ) 

Large crab grass ( Digitaria sp . ) 



Oj 


Occur 


Coverage 


rence 


40.1 


73.0 


14.3 


0.4 


14.3 


19.0 


9.6 


27.0 


8.7 


25.0 


3.6 


14.0 


3.5 


15.0 


2.4 


9.0 


2.2 


14.0 


2.0 


15.0 


1 .8 


30.0 


1 .4 


4.0 


1 .2 


7.0 


1 .2 


8.0 


1 .1 


14.0 


1 .0 


8.0 


0.6 


1.0 


0.5 


3.0 


0.5 


1.0 


0.4 


4.0 


0.4 


12.0 


0.4 


1.0 


0.1 


1.0 


0.1 


trace 


0.1 


trace 


0.1 


1.0 


0.1 


4.0 


0.1 


1.0 


0.1 


trace 


0.1 


trace 


0.1 


trace 


trace 


1 .0 


trace 


1 .0 


trace 


trace 


trace 


trace 



5-73 



Table 5-25, Average Height, Percent Occurrence, and Average 
Percent Coverage of the Major Moist-Soil Plant 
Species by Transect at the Rice Lake Study Areas, 
September 1978. 





Southern 


Area Transects 


Northern Area 


Transects 


Species 


Variable 


IS 


2S. 


3S 


TN 


2N 


3N 


Teal 
Grass 


Ave . ht . , m 
% Occur. 
Ave. % Gov. 


0.06 
65.0 
2.9 


0.12 
100.0 
62.4 


0.09 
100.0 
16.7 


0.09 
100.0 
42.1 


0.0 5 
100.0 
17.6 


0.07 
95.0 
6.0 


Rice 
Cut- 
grass 


Ave . ht . , m 
% Occur. 
Ave. % Cov. 








0.18 
20.0 
1 . 1 


0.15 
40.0 
1 .6 


0.18 
75.0 
2.5 


Wild or 

Duck 

Millet 


Ave . ht . , m 
% Occur. 
Ave. i Cov. 


0.49 
15.0 
1 .0 


0.37 
10.0 
0.3 




0.27 
25.0 
0.6 






Japanese 
Millet 


Ave . ht . , m 
% Occur. 
Ave. % Cov. 


0.43 
50.0 
5.6 


0.52 
75.0 
12.1 


0.52 
89.0 
28.9 


0.46 
95.0 
11 .6 


0.15 
85.0 
5. 1 


0. 13 
5.0 
0. 1 


Walter 's 
Millet 


Ave . ht . , m 
% Occur. 
Ave. % Cov. 


0.40 
15.0 
0.4 


0.37 
65.0 
0.8 


0.52 
22.0 
5.9 


0.37 
15.0 
0.4 






Awned 
Cyperus 


Ave . ht . , m 
1 Occur. 
Ave. % Cov. 










0.09 
70.0 
18.5 


0.09 
70.0 
20.0 


Chufa 


Ave. ht., m 
% Occur. 
Ave. % Cov. 


0.09 
90.0 

2.3 


0.21 
100.0 
37.1 


0.61 
100.0 
34.0 


0.12 
100.0 
17.6 


0.22 
100.0 
30.9 


0.27 
95.0 
30.1 



Nodding Ave. ht., m 
Smart- ^o Occur, 
weed Ave. % Cov. 



0.37 0.61 
55.0 83.0 
3.3 8.3 



0.21 0.18 0.30 
5.0 80.0 48.0 
0.1 2.0 3.9 



Largeseed Ave. ht., m 
Smart- % Occur, 
weed Ave. i Cov. 



0.45 
trace 
trace 



Pigweed Ave. ht., m 0.09 
% Occur. 100.0 
Ave. I Cov. 4.4 



0.46 0.67 
100.0 100.0 
48.3 65.1 



0.15 0.18 0.30 
100.0 100.0 100.0 
4.4 20.6 13.5 



Beggar- Ave. ht., m 0.09 0.24 0.49 
ticks % Occur. 25.0 25.0 28.0 
Ave. % Cov. 6.2 6.2 12.1 



0.15 0.18 0.30 
85.0 100.0 100.0 
7.1 7.4 21.6 



5-7' 



Table 5-26 



Average Height, Percent Occurrence, and Average 
Percent Coverage of the Major Moist-Soil Plant 
Species by Transect at Spring Lake, September 1978 





Variable 

Ave. ht . , m 
% Occur. 
Ave. % Gov. 








Transect 










Species 


1 




2 


> 


3 

0.18 

2.0 

0.3 


4 


c 


5 


Teal grass 


0. 
41 . 
13. 


18 



4 


0. 

19. 

3. 


,18 



,4 




Rice 
Cutgrass 


Ave . ht . , m 
% Occur. 
Ave. % Gov. 


0. 

39. 

7. 


79 

,6 


0. 

19. 

1 . 


,87 
.0 

,7 


0.94 
12.0 
0.5 










Wild or 

Duck 

Millet 


Ave . ht . , m 
% Occur. 
Ave. Gov. 


0. 
2, 
0. 


,55 

,0 

.1 
















Japanese 
Millet 


Ave ht . , m 
% Occur. 
Ave. % Gov. 


1 . 

10. 

1 . 


,04 
.0 

.7 


0, 

13, 

1 , 


.62 

.0 

,5 


1 .07 

4.0 

0.3 


0, 
7, 
0, 


.49 

.0 

.8 


0, 
64, 

22, 


.98 

.0 

.0 


Red-rooted 
Nutgrass 


Ave . ht . , m 
% Occur. 
Ave. % Gov. 


0, 
94, 
66, 


.94 

.0 

.3 


1 , 

72, 
47, 


.10 

.0 

.6 


1 .16 
35.0 
17.0 


0, 
86, 
36, 


.91 

.0 

.4 




77 
21 , 


.82 

.0 

.2 


Nodding 
Smartweed 


Ave. ht . , m 
'o Occur. 
Ave. b Gov. 


0, 

29, 

2, 


.76 
.0 

.2 


1 , 

14, 

3. 


.28 

.0 

.4 


1 .09 

8.0 

0.4 


1 , 
50, 
28, 


.55 
.0 

.7 


1 

29, 
10, 


.34 

.0 

.3 


Largeseed 
Smartweed 


Ave . ht . , m 
'o Occur. 
Ave. % Gov. 


0, 
0, 
0, 


.58 

.1 

.1 


1 , 
41 , 
36, 


.52 
.0 
. 1 








1 

55 

27 


.12 

.0 

.0 


L a d )' ' s 

Thumb 

Smartweed 


Ave . ht . , m 
% Occur. 
Ave. % Gov. 












0, 
0, 

3, 


.79 

.7 

.0 






Swamp 
Smartweed 


Ave . ht . , m 
% Occur. 
Ave. Gov. 






1 
1 
1 


.5 
.0 
.0 


0.79 

4.0 

0.9 










Pigweed 


Ave. ht . , m 
% Occur. 
Ave. % Gov. 



2 



.05 
.0 
. 1 


1 

2 



.31 

.0 

.4 












Beggar- 
ticks 


Ave . ht . , m 
% Occur. 
Ave. % Gov. 




25 
2 


.52 

.0 

.5 



35, 
10 


.98 

.0 

.6 


1 .65 

71 .0 
46.7 


0, 

53, 
8, 


.83 

.0 

.8 


1 , 
6, 
1 , 


.07 
.0 
, 3 



5-75 
Vegetation 

Rice Cutgrass (Leersia oryzoides) 

Rice cutgrass ( Leers ia oryzoides ) was reported by Mohlen- 
brock (1975: 137) as occurring occasionally throughout 
Illinois on low, moist soil. Rice cutgrass occurred on 15.0° 
and covered an average of 2.01 of the sample plots at Spring 
Lake. At Rice Lake, rice cutgrass occurred on 23. Ot and 
covered an average of 0.9b of the sample plots (Table 5-23). 

Rice cutgrass grew the tallest (0.94 m; 3.08 ft) at Spring 
Lake on the most water-saturated soil of transect 3 (Table 
5-26). Low and Bellrose (1944: 17) found that rice cutgrass 
produced more seed in the Illinois River valley when it was 
growing in 15.2 cm (6 in) of water rather than on dry soil. 
Kadlec (1960: 275) indicated that in a Michigan waterfowl 
impoundment, rice cutgrass occurred predominantly in areas 
where seepage or the ground water kept the soil moist. The 
greatest percent occurrence (39.0) and average percent 
coverage (7.6) of rice cutgrass occurred on transect 1 at 
Spring Lake (Table 5-26) . This transect was exposed by draw- 
down during mid-June and was the last to be exposed. Uhler 
and McGilvery (1969: 3) found that drawdown by June in a 
Maryland waterfowl impoundment resulted in heavy growth of 
red-rooted nutgrass and increased coverage of rice cutgrass. 
The primary plant species that occupied transect 1 at 
Spring Lake was red-rooted nutgrass (Table5-26 ) . However 
optimum growth of rice cutgrass occurred on transect 3, pos- 
sibly because of the water-saturated soil. The early expo- 
sure of the soil on transect 3 resulted in heavy stands of 
Bidens sp. that probably overshadowed the latter developing 
rice cutgrass. The late drawdown on transect 1 favored 
germination of rice cutgrass, but the soil probably was not 
moist enough for vigorous growth. 

Rice cutgrass only occurred on the northern study area 
at Rice Lake. The greatest height, average percent coverage, 
and occurrence of rice cutgrass at Rice Lake occurred on 
transect 3N (Table 5-25). This transect had the driest soil 
and was the first to be exposed by drawdown. As a result of 
the extremely late drawdown a't Rice Lake (August), the rice 
cutgrass that germinated on transect 3N had the longest 
time to grow. 

Bellrose and Anderson (1943: 432) rated rice cutgrass 
as the number one duck food plant in the Illinois River valley. 
Martin and Uhler (1939: 47) found that rice cutgrass com- 
prised more than one-fifth of the food of 87 mallards col- 
lected during the fall in the floodplain along the Illinois 
River. Rice cutgrass ranked thirteenth in seed production in 



5-76 
Vegetation 



the Illinois Valley, however its rootstocks (which are also 
a means of propagation) and shoots add greatly to the amount 
of food the plant provides. The average seed production of 
rice cutgrass is 80 cc/m2; lqw and Bellrose (1944: 13) indi- 
cated its yield is generally correlated with water depth. 
They found the seed yield of rice cutgrass growing in 
15.2 cm (6 in) of water was 158 cc/m^, whereas the yield in 
soil with a water table 15.2-38.1 cm (6-15 in) below the 
surface was approximately 50 cc/m2. For full production 
and maximum utilization of seeds and rootstocks by water- 
fowl, the ground surface should be covered by 2.5-5.1 cm 
(1-2 in) of water during the growing season and autumn (Low 
and Bellrose, 1944: 17) . 

Millets (Echinochloa sp.) 

Three species of millets, Walter's ( Echinochl oa Walteri ) , 
wild (E. crusgalli ) , and Japanese (E.c. f rument accaT occur 
througKout most of the Illinois River valley . All were 
found growing at Rice Lake. Only Japanese and wild millets 
occurred at Spring Lake study area. 

The millets comprise one of the most important waterfowl 
food resources in the Illinois River valley. Bellrose and 
Anderson (1943: 432) rated Walter's millet as the second 
most important waterfowl food in the Illinois Valley and wild 
and Japanese millets were ranked third. Low and Bellrose 
(1944: 11) found that wild millet was the top seed producer 
among 27 waterfowl food plants studied, yielding an average 
of 457 cc/m^ of seeds. Wild millet was found to be a 
particularly consistent producer. In California, Millar 
and Arend (1960: 1) reported an average yield of 680.4 kg 
of seed per hectare (1,500 lbs per acre) and yields of more 
than 1,360.8 kg (3,000 lbs) have been produced. Japanese 
millet produced an average seed yield of 455 cc/m^, whereas 
Walter's millet produced 306 cc/m^. Although wild and 
Japanese millets produce more seed, Walter's millet, as 
indicated by its consumption by waterfowl, was ranked the 
highest. This may be due to several factors: pintails and 
teals may actually prefer the smaller seeds of Walter's mil- 
let; many seeds of Japanese millet shatter and germinate in 
the same season; and blackbirds consume more seeds of wild 
and Japanese millet than of Walter's millet (Low and Bellrose, 
1944: 12). 

Japanese Millet 

Japanese millet had the 4th highest average percent 
coverage (10.3°£,) and occurrence (66 . 0'a ) at Ri ce Lake and the 



5-77 
Vegetation 



seventh highest average percent coverage (3.5°o) and occur- 
rence (15.0b) at Spring Lake (Tables 5-23, 5-24). 

Japanese millet does not volunteer as readily as wild 
and Walter's millet and, therefore, must be sown yearly for 
maximum production (Low and Bellrose, 1944: 11; Crail, 1951: 
1; Millar and Arend, 1960: 10). Japanese millet was sown by 
Department of Conservation personnel at Spring and Rice 
lakes during the summer of 1978. As a result of this seeding, 
the frequency of occurrence and the percent coverage of 
Japanese millet at these lakes is related to the soil con- 
ditions and the amount of seed that was sown on each transect. 
Therefore, only the average height can be used to discuss 
the effects of various environmental factors on Japanese 
millet at Rice and Spring lakes. 

Japanese millet was aerial-seeded after moist-soil plants 
had germinated on most of the mud flats at Spring Lake. Only 
low wet areas on these transects that were exposed last by 
drawdown were aval lable for germination of Japanese millet. 
The greatest average heights of Japanese millet occurred on 
transects 3, 1, and 5 (Table 5-26). This was probably a result 
of less competition from tall plants such as nodding and 
largeseed smartweeds that dominated transects 2 and 4. 
Japanese millet attained approximately the same height on 
IN and IS, the lowest and wettest transects at Rice Lake. 
The average height on transects 2N and 3N appears to be sig- 
nificantly lower than those of transects 2S and 3S (Table 5- 
25 ) . Transects 2N and 3N were shaded from the morning 
sun by large silver maple and cottonwood trees that bordered 
the northern study area. The shade from these trees may 
have significantly lowered the soil temperature and inhibited 
the germination of Japanese millet. 

Optimum germination of Japanese millet occurs on moist 
soil (Bellrose, 1941: 277). Japanese millet tolerates less 
flooding and can grow under drier conditions than wild mil- 
let (Millar and Arend, 1960: 15). We observed 0.5-1.1 m 
(1.5-3.35 ft) tall Japanese millet growing in 10.2-15.2 cm 
(4-6 in) of water during 1978 at Spring Lake, indicating 
that Japanese millet can withstand slight inundation after 
germination. 

Walter's Millet 

Walter's millet was not found at Spring Lake. Walter's 
millet covered an average of ^.Z% of and occurred on 23.0° of 
the sample plots at Rice Lake (Table 5-23)- Walter's millet 
did not occur on transects 2N and 3N (Table S-25) . 



5-78 
Vegetation 



Shading by trees in the morning may have resulted in 
soil temperatures too low for germination of Walter's millet, 
The largest average percent coverage and height of Walter's 
millet occurred on transect 3S and may have been a result of 
a longer growing season (Table 5-25). The greatest percent 
occurrence was on transect 2S and may have resulted from 
less plant competition than occurred on transect 3S (Table 
5-25). 

Walter's millet generally germinates on wetter soil 
than Japanese millet and drier soil than wild millet. 
However, as a result of the seeding of Japanese millet on 
the mud flats at Rice Lake, this relationship is not 
shown in Table 5-25, 

Wild Millet 

Wild or duck millet appeared on 8.01 and covered an 
average of 0.3% of the sample plots at Rice Lake (Table 5-23). 
Wild millet only occurred in two plots at Spring Lake 
(Table 5-24) . 

The greatest average percent coverage and occurrence 
and height of wild millet occurred on transects IN, IS, or 
2S at Rice Lake (Table 5-25), Wild millet did not occur on 
transects 3S , 2N, and 3N . These data indicate that wild 
millet inhabited the lowest and wettest soil at Rice Lake. 
Wild millet occurred only twice on transect 1 at the Spring 
Lake study area. This transect was the lowest, wettest, 
and the last to be exposed. 

Martin and Uhler (1939: 50) indicated that wild mil- 
let thrives in soils that are submerged by a few inches of 
water during the early part of the growing season but are 
exposed later in the summer and autumn. Wild millet pre- 
fers moist soil and mud flats for germination and growth. 
However, Millar and Arend (I960: 2) indicated that wild 
millet growing in California will germinate in 15.2 cm 
(6 in) or less of water. They also found that after young 
wild millet plants become established and emerge from the 
water, they can withstand continued flooding. Hall, Pen- 
found, and Hess (1946: 41) indicated that in the Tennes- 
see Valley, wild millet 0.91 m (3 ft) tall was destroyed 
by inundation of silty water 0,30-1.61 m (1-2 ft) deep 
during 5 7.0 "b of the period from II July to 22 September. 
Wild millet was not observed to germinate or grow in standing 
water at Rice and Spring lakes. 



5-79 



Vegetation 



Nutgrasses (Cyperus sp.) 

A total of five species of nutgrasses ( Cyperus sp.) 
were found growing on mud flats at Spring and Rice lakes (Tables 
5-25 5 5-24). Three of the 5 species found, straw-colored 
nutgrass (C. strigosus ) , red-rooted nutgrass (C. erythro - 
rhizos ) , and chufa (C, esculentus ) , were noted as being 
common throughout IlTinois by Mohlenbrock (1960: 273). 
Awned cyperus (C. inf lexus ) is found sparingly throughout 
Illinois and shTning cyperus (C. rivularis ) is found mostly 
in northern Illinois (Mohlenbrotk, 1975: 141). 

Red-rooted Nutgrass 

Red-rooted nutgrass covered the greatest area (40.1?.) 
and occurred more frequently (73.01) than any other plant 
at Spring Lake (Table5-24). However, it was not found at 
Rice Lake. Mohlenbrock (1960: 276) described red-rooted 
nutgrass as an annual with fibrous, often red roots sup- 
porting culms up to 1.30 m (4.3 ft) tall, but occasionally 
was dwarfed to 1 cm (0.4 in). It is commonly found on 
moist, often sandy soil. Red-rooted nutgrass attained its 
greatest height at Spring Lake on transect 3 followed by 
transect 2 (Table 5-26). Sections of transects 2 and 3 
were on mud flats that were exposed by early drawdown in 
mid-May. This longer growing season was probably respon- 
sible for the great height attained by red-rooted nutgrass 
on these transects. 

Uhler and McGilvrey (1969: 3) reported exposure of 
mud flats by June resulted in heavy growth of red-rooted 
nutgrass in Maryland. Hall, Penfound, and Hess (1946: 29) 
indicated that mud flats exposed from June through October 
in the Tennessee Valley supported heavy growth of red- 
rooted nutgrass. At Spring Lake, we found that the greatest 
percent occurrence and coverage of red-rooted nutgrass was 
on transect 1, an area that was exposed by drawdown in 
mid-June (Table 5-26). 

Hall, Penfound, and Hess (1946: 40) reported that 
red-rooted nutgrass withstood an inundation of 15.2 cm 
(6 in) for 30 days during June in the Tennessee Valley; 
however, no mention was made of the height or maturity of 
the plants. Weller and Fredrickson (1973: 276) indicated 
that, in general, nutgrasses disappear in the first or 
second year after flooding. We observed that complete in- 
undation of the entire plant for 2 weeks during August, 1977, 
at Lake Chautauqua (Mason County, La Grange Pool) decimated 
mature plants of red-rooted nutgrass. The amount of inun- 
dation nutgrasses can withstand is dependent upon the height 



5-1 



Vegetation 



and maturity of the plant. In general, the greater the 
depth of flooding (or the smaller the percentage of shoot 
surface exposed to the atmosphere), the more quickly indi- 
viduals of a given species succumb. 

Nutgrasses as a group were rated by Bellrose and Anderso 
(1943: 432) as the fifth most important duck food in the 
Illinois River valley. Based on the availability and con- 
sumption by waterfowl, red-rooted nutgrass was ranked as 
the second most important nutgrass in the Illinois Valley. 
Low and Bellrose (1944: 12) found that red-rooted nutgrass 
yielded 91 cc/m^ of seed in the Illinois Valley, making it 
the fourth most productive waterfowl food plant sampled in 
lakes with fluctuating water levels. Uhler and McGilvrey 
(1969: 3) found that green-winged teal and mallard use- 
days increased three fold when a waterfowl impoundment 
in Maryland produced a lush stand of red-rooted nutgrass. 

Chufa 

Chufa ranked second in average percent coverage (25.2?i) 
and occurrence (97.0'o) to pigweeds ( Acnida sp . ) and it was 
the most common nutgrass at Rice Lake (Table 5-23) . Chufa 
was not found at Spring Lake. 

Mohlenbrock (1960: 278) described chufa as a peren- 
nial arising from numerous conspicuously scaly rhizomes 
that terminate in a small hard tuber and with rather stout 
culms up to 1.0 m (3.3 ft) tall. It is found in moist, fre- 
quently cultivated soil. Chufa attained its greatest average 
height on transect 3S followed by transect 3N (Table 5-25) . , 
Transects 3S and 3N were located the highest and farthest 
from the water line. Correspondingly these transects were 
the driest and were exposed earlier by drawdown. Therefore, 
the chufa sampled on these transects had more time to grow 
resulting in their large height. 

Crail (1951) studying moist-soil plants in Missouri 
found that the lowest and last mud flats exposed during a 
June drawdown supported a stand of chufa. He noted that chufa 
was found in the upper section of the mud flats, but it 
could not successfully compete with wild millet ( Echinochloa 
crusgalli ) . Chufa was also observed germinating in Missouri 
when mud flats were exposed after the middle of July (Horman, 
1955: 50). We observed chufa growing on all transects at 
Rice Lake, indicating that it could have germinated as early 
as the end of July and as late as 15 September. 



5-81 
Vegetation 



The percent occurrence for chufa varied little (90.0*- 
100. 01) on the transects at Rice Lake (Table 5-25). The 
average percent coverage was lowest on transect IS followed 
by transect IN (Table 5-25) . Transects 2S and 3S varied 
slightly and averaged 35. 6d coverage whereas transects 2N 
and 3N were almost identical and averaged 30.51> coverage 
(Table 5-25) . The greater coverage on transects 2 and 3 
from both study areas may be a result of two factors: 
(1) a longer exposure period of these areas resulting in 
a longer growing season, and (2) drier soil conditions. 
The soil was saturated with water at transects IS and IN 
while the soil on transects 2 and 3 from both areas was 
not, thus indicating that chufa probably prefers drier 
soils . 

Bellrose (1941: 275) indicated that chufa can stand 
irregular water level fluctuations. We observed that com- 
plete inundation for two weeks at Lake Chautauqua during 
August, 1977, decimated heavy stands of chufa. 

Low and Bellrose (1944: 12) found that in the Illinois 
River valley, chufa produced an average of 30 cc/m^ of seed. 
Although red-rooted and straw-colored nutgrasses produce 
more seed, a greater amount of chufa seeds were consumed 
by waterfowl making it the most important nutgrass in the 
Illinois Valley. Chufa was a preferred food of blue-winged 
and green-winged teals, and pintail (Anderson, 1959: 334). 
These species of waterfowl consume the seeds, seed heads, 
and tubers of chufa. 

Chufa reproduces by tubers and seeds. The tubers 
must be exposed to low winter temperatures before they 
will germinate in the spring (Tumbleson and Kommedahl, 
1962: 189). Tests indicate that the seeds of chufa also 
require an after-ripening period before they will germinate 
(Justice, 1946: 314). 

Awned Cyperus 

Awned cyperus occurred on 24.01 of the plots sampled at 
Rice Lake and covered an average 5.7-0. This nutgrass was 
not found at Spring Lake. 

Mohlenbrock (1960: 291) described awned cyperus as an 
annual with fibrous roots forming a dense mat with very 
slender culms 3-15 cm (1.2-5.9 in) tall, and having a 
purplish tinge at the base. We found that awned cyperus 
attained a height of 0.09 m (0.3 ft) on transects 2N and 
3N at Rice Lake. Because awned cyperus was found only at 
the north study area, we believe that the taller plant 



5-82 
Vegetation I 



canopy and resulting shade at the south study area may have 
prevented the establishment of this minute plant. 

Awned cyperus occurred on an average of 70.01. of the 
plots sampled in transects 2N and 3N while it covered an 
average of 18.51, of the plots in transect 2N and 20.01, 
in transect 3N . Apparently this nutgrass prefers soil 
that is not completely saturated such as that in transect 
IN. 

Although no information on the tolerance to inunda- 
tion by awned cyperus was found, we believe that it will 
expire if exposed to complete inundation for an extended 
period . 

Awned cyperus is found only sparingly throughout 
Illinois (Mohlenbrock, 1960: 273). Therefore, information 
on its palatability and consumption by waterfowl or other 
vertebrates is unknown. However, if the seed is available 
on mud flats, it will probably be consumed to some degree 
by migrating waterfowl both in the fall and spring. 

Shining Cyperus and Straw- Colored Nutgrass 

Shining cyperus occurred only at Spring Lake whereas 
straw-colored nutgrass occurred at both Spring and Rice 
lakes. Neither plant occurred frequently nor covered a 
significant portion of either study area, thus precluding 
a discussion of plant coverage, occurrence, and height. 
However, when proper growing conditions occur, straw- 
colored nutgrass has been shown to be an important duck food 
plant. Therefore, findings from the literature will be 
discussed . 

Mohlenbrock (1960: 289) described straw-colored nut- 
grass as a perennial growing from a hard corm-like rhizome 
with culms reaching 1.20 m (3.9 ft) in height. It grows 
in very moist soil in possibly every county of Illinois. 
Low and Bellrose (1944: 12) found that in the Illinois 
Valley, straw-colored nutgrass yielded approximately 50 
cc/m of seeds, a yield less than that of red-rooted 
nutgrass but more than chufa. However, Bellrose and An- 
derson (1943: 425) indicated that migrating waterfowl 
selected straw-colored nutgrass after red-rooted nutgrass 
and chufa, thus making it the third most important nutgrass 
consumed by waterfowl in the Illinois- River valley. Ander- 
son (1959: 334) found that straw-colored nutgrass ranked high 
among the important foods preferred by migrating pintail 
and blue-winged and green-winged teals in the Illinois 
Valley. 



5-83 
Vegetati on 



Straw-colored nutgrass, like most of the nutgrasses, 
can probably withstand inundation after the plants reach a 
certain degree of maturity provided that they are not over- 
topped for an extended period. We have observed that 
inundation of the entire plant for a period of 2 weeks 
during August, 1977, at Lake Chautauqua killed mature 
plants . 

McDonald (1955: 30) found that straw-colored nutgrass 
in a marsh on Lake Erie germinated and dominated areas that 
were the first to be exposed during the summer. We found 
straw-colored nutgrass growing on a mud flat exposed by 
the end of July at Rice Lake and on a mud flat exposed by 
mid-May at Spring Lake. 

For the seeds of nutgrasses and other moist-soil food 
plants to be available to waterfowl in the fall, the seed 
heads or at least the plants themselves must be inundated. 
During the spring, the seeds are strained by waterfowl from 
the bottom substrate or from the water surface. When the 
seed production of nutgrass is poor or absent, seeds produced 
from previous years are still present in the bottom material 
and can be fed upon by waterfowl (Bellrose and Anderson, 
1940: 420). The ability of nutgrasses to produce seed after 
germinating late in the growing season coupled with the 
availability of their seeds throughout the year make them 
extremely important to waterfowl in the Illinois Valley. 

Smartweeds (Polygonum sp.) 

A total of four species of smartweeds ( Polygonum sp.) 
were found growing on mud flats at Spring and Rice Takes. 
Three of the four species found, lady's thumb (P. persi - 
caria ) , nodding smartweed (P. lapthi folium ) , an3 large- 
seed smartweed (P. pcnnsylvanicum ) , were noted by Mohlenbrock 
(1975: 216-217) as occurring throughout Illinois. Swamp 
smartweed (P. hydropiperoides ) was recorded as occurring 
occasionally to commonly throughout the state (Mohlenbrock, 
1975: 216). 

The moist-soil smartweeds are highly palatable and 
actively sought by waterfowl. Bellrose and Anderson (1943: 
432) rated smartweeds as the fourth most important group of 
waterfowl food plants in the Illinois River valley. Large- 
seed smartweed produces the greatest seed yield (100 cc/m"^) 
followed by nodding smartweed (78 cc/m ) and swamp smartweed 
(44 cc/m ) in the Illinois Valley (Low and Bellrose, 1944: 
13). The seed yield of lady's thumb smartweed was not 



5-84 
Vegetation 



determined; Martin and Uhler (1939: 79) rank this smartweed 
as a fair waterfowl food plant. 

Larceseed Smartweed 

W! 

Largeseed smartweed ranked third in average percent 
coverage (14.3a) and sixth in percent occurrence (19.06) at 
Spring Lake (Table 5-24). At Rice Lake, largeseed smartweed 
and straw-colored nutgrass shared the lowest average percent 
coverage (trace) and occurrence (1.01.) (Table 5-25). 

The stems of largeseed smartweed are erect and ascend 
to 2.30 m (7.5 ft) tall (Mitchell and Dean, 1978: 47). 
Largeseed reached 1.52 m (5.0 ft) in height on transect 
2, 1.12 m (3.7 ft) on transect 5, and 0.58 m (1.9 ft) 
on transect 1 at Spring Lake. The only plant found at 
Rice Lake reached 0.45 m (1.5 ft) in height on transect 
3N. Harmon (1955: 50) noted that in Missouri largeseed 
smartweed did not germinate on any area that had water-sa- 
turated soil. This indicates that aeration may be a 
factor in promoting the germination of largeseed smartweed. 
Although transect 2 was not the earliest to become exposed 
by drawdown at Spring Lake, it was one of the driest, thus 
possibly resulting in the greatest average height found for 
largeseed smartweed. Transect 3 at Spring Lake was ex- 
posed earlier than transect 2, but as a result of spring- 
water seepage, the soil was saturated and largeseed smart- 
weed did not appear. Crail (1951: 7) found that in 
central Missouri, smartweeds are more likely to develop on 
earlier established mud flats, especially those formed prior 
to 15 June. The late drawdown at Rice Lake resulted in 
a short growing season and left little time for the soil 
to dry. The short growing season and wet soil at Rice Lake 
are probably the principal reasons largeseed smartweed 
development was poor. 

Largeseed smartweed occurred most often at Spring Lake 
on transect 5 and covered the greatest percentage of the 
sample plots on transect 2 (Table 5-26). Transect 5 was one 
of the first transects to be exposed by drawdown and this 
early exposure may have been the reason that largeseed 
smartweed occurred most abundantly there. The greatest 
average percent coverage on transect 2 may be a result of 
the drier soil providing optimum growth conditions. 

In general, the growth of smartweeds is favored by an 
early drawdown (Crail, 1951: 7). However, Harmon (1955: 
57) indicated that germination of several moist-soil plants 
is a result of an important relationship between soil tem- 
perature and soil moisture in relation to water levels. He 



5-85 
Vegetation 



found that germination of nodding smartweed favored cooler 
temperatures (15.6 C, 60 F) than largeseed smartweed (25-26.7 
C, 77-80 F) . Soil temperature is possibly a factor respon- 
sible for the germination of smartweeds in different zones 
on the transects at Rice and Spring lakes. 

Largeseed smartweed of unknown height and maturity 
was observed to survive 30 days of flooding with 0.30 m 
(1 ft) of water during the month of June in the Tennessee 
Valley (Hall, Penfound, and Hess, 1946: 40). Keller and 
Fredrickson (1973: 276) noted that smartweeds- mostly 
disappeared from a flooded Iowa lake in the first or second 
year, except along the shore margins. Largeseed smartweed 
was not observed growing in standing water or saturated 
soil at Spring Lake. Mature largeseed smartweed plants 
will probably withstand some degree of flooding, but 
seedlings may not survive inundation. 

Nodding Smartweed 

Nodding smartweed ranked fifth in average percent 
coverage (8.71>) and occurrence (25.0°) at Spring Lake 
(Table 5-24). Although nodding sm.artweed occurred on 48.0°6 
of the plots sampled at Rice Lake, it only ranked tenth 
in coverage (2.84°6) (Table 5-23). 

The stems of nodding smartweed are described by 
Mitchell and Dean (1978: 46) as decumbent to strongly 
erect-ascending, growing up to 2.50 m (2.7 ft) tall from 
a twisted annual taproot. Nodding smartweed grew tallest 
at Rice Lake on transects 3S and 3N (Table 5-25) . Because 
of the late drawdown at Rice Lake, the soil on the mud 
flats remained saturated throughout most of the short 
growing season. As a result of the extremely moist soil, 
nodding smartweed attained its greatest height on the 
highest and driest transects (3S and 3N) . The maximum 
height of nodding smartweed at Spring Lake occurred on 
transect 4 followed by transect 5 (Table 5-26), both of 
which had many dry areas from early drawdown. These dry 
areas supported the most vigorous stands of largeseed 
smartweed. Meeks (1969: 217) indicated that nodding 
smartweed production was greatest during a May drawdown 
when compared to drawdowns in March, April, and June. 
Transects 4 and 5 were exposed by mid-May; however, several 
low wet areas persisted throughout the growing season on 
these transects. Both the early drawdown and moist areas 
that were not inhabited by largeseed smartweed probably 
favored germination of nodding smartweed and resulted in 
optimum growth. 



5-86; 
I 
Vegetation 



Nodding smartweed occurred most often at Spring Lake on 
transect 4 followed by transects 5, 1, 2, and 3 (Table5-26). 
The greatest percent coverage of nodding smartweed at 
Spring Lake was found on transect 4 followed by transects 5, 
2, 1, and 3 (Table 5-26). The ranking of these transects is 
somewhat similar for both percent coverage and occurrence 
and probably is a result of several factors. Early drawdown 
on transects 4 and 5 undoubtedly favored smartweed germination. 
However, the moist areas on transects 4 and 5 probably 
favored germination of nodding rather than largeseed smart- 
weed and resulted in the correspondingly high percent occur- 
rence and coverage of the nodding species. A late drawdown 
on transect 1 resulted in dominance by red-rooted nutgrass. 
Nodding smartweed however, occurred as frequently on 
transect 1 as on number 5, Transect 2 was probably too 
dry for development of nodding smartweed and was domina- 
ted by largeseed smartweed. Transect 3 remained in a 
marshy condition for most of the growing season, proving 
too wet for development of nodding smartweed and thus re- 
sulting in the lowest percent occurrence and coverage of 
this species. 

Nodding smartweed occurred most often on transects 3S 
and 2N at Rice Lake, whereas the greatest percent coverage 
of nodding smartweed was found on transects 3S and 3N (Table 
5-25) . A late drawdown at Rice Lake resulted in saturated 
soil on the mud flats throughout most of the short growing 
season. The saturated soil and short growing season probably 
resulted in the greatest percent occurrence and coverage 
of nodding smartweed found on the drier transects at Rice 
Lake . 

Bellrose (1941: 275) indicated that nodding smartweed 
can withstand some degree of fluctuating water levels. Nod- 
ding smartweed of unknown maturity and height was observed 
to tolerate a 0.30-m (1-ft) flood for 30 days during June 
in the Tennessee Valley (Hall, Penfound, and Hess, 1946: 
40). Van Der Valk and Davis (1978: 362) noted that nodding 
smartweed germinated on extremely moist soil. When the 
seedlings were inundated with 10 cm (3.9 in) of water, none 
of them survived. Mature nodding smartweed plants appear 
to be tolerant of water level fluctuations; however, 
seedlings and young plants may not survive inundation. 

Swamp and Lady ' s Thumb Smartweeds 

Swamp and lady ' s thumb smartweeds occurred infrequently 
and covered less than one percent of the Spring Lake study 
area (Table 5-24) . Neither swamp nor lady's thumb smartweed? 
occurred at Rice Lake. 



5-87 
Vegetation 



Isolated stands of swamp smartweed were found growing in 
low wet spots on transects 2 and 3 at Spring Lake. Hall, 
Penfound, and Hess (1946: 46) and Taylor (1977: 19) noted 
that swamp smartweed grew in shallow water throughout most 
of the growing season. The largest stands of swamp 
smartweed were found on transect 3 growing in areas that 
held water through the entire growing season. 

Lady's thumb smartweed was found growing only on 
transect 4 that had both a dry soil and a very moist soil 
area. The largest stand of lady ' s thumb smartweed was 
growing on the area that had moist soil. 

Pigweed (Acnida sp.) 

Pigweeds ( Acnida sp.) only occurred on ^ .0% of and 
covered an average of . 1 -o of the plots sampled at 
Spring Lake (Table 5-24). Pigweed was found growing once 
on transect 1 and twice on transect 2. Plant competition 
is possibly the factor responsible for the low abundance 
of pigweeds at Spring Lake. 

Although pigweed was common at Rice Lake, a preference 
for the transects with drier soil is apparent when the 
average height and percent coverage of pigweeds on the 
transects is considered (Table 5-25) . Bellrose and 
Anderson (1943: 428) noted that pigweeds ( Acnida tuber - 
culata ) grew on drier sites than other moist-soil plants. 

Pigweeds require exposed mud flats for germination. 
Bellrose (1941: 275) indicated that pigweeds have the 
ability to grow under conditions resulting from irregular 
water level fluctuations. However, we observed that 
complete inundation of the entire plant for 2 weeks during 
August, 1977, at Lake Chautauqua (Mason County) decimated 
mature pigweed plants. 

Pigweed ( Acnida tuberculata ) was ranked by Bellrose 
and Anderson (1943: 432) as the fourteenth most important 
duck food in the Illinois Valley. Low and Bellrose (1944: 
12) found the average yield of pigweed in the Illinois 
Valley was 85 cc/m2 of seeds. Because submerged aquatic 
duck food plants are no longer common in the Illinois 
River valley (see section on suJ'ncrgcnt plants, pages 5-52 through 5-59) 
pigweeds are more important as a duck food. The seeds of 
this plant are readily consumed by the dabbling ducks, es- 
pecially the mallard, pintail, and green- and blue-winged 
teals. 



I 

I 

5-8'i 



Vegetat i on 



Seggar-ticks (Bidens sp . ) 



Beggar-ticks covered an average of 40.16 and occurred 
on 40.0fc of the sample plots at Spring Lake, whereas at 
Rice Lake, beggar-ticks covered an average of only 6.7° of 
the sample plots but occurred on 61.0° (Tables 5-23 ^ 5-24). 

The greatest average height, percent occurrence, and 
average percent coverage of beggar-ticks was on transect 3 at 
Spring Lake (Table 5-26). The soil on this transect was 
saturated with spring water and standing water up to 10.2 cm 
(4 in) deep was encountered in several places. Beggar-ticks 
over 1.82 m (6.0 ft) tall were observed growing in standing 
water on transect 3. Kadlec (1960: 90) found Bidens 
cenura growing in water that ranged from 10.2-15.2 cm (4-12 
in) JFep at a Michigan waterfowl impoundment. However 
Weller and Fredrickson (1973: 276) indicated that Bidens 
cernua in an Iowa marsh "mostly disappeared in the first or 
second year after flooding except along the shore zone." 
Taylor (1977: 18) indicated that Bidens spp. was found growing 
on relatively high and dry soil in a Missouri waterfowl 
impoundment. Apparently beggar-ticks are tolerant of a 
wide range of soil moisture conditions. 

The next tallest average height, the second largest 
percent occurrence, and average percent coverage of beggar- 
ticks at Spring Lake occurred on either transect 2 or 4 
(Table 5-26) . The areas that Bidens occupied on these 2 
transects were exposed early (16 May 1978). The greatest 
average height, percent occurrence, and average percent 
coverage at Rice Lake occurred on the transects that were 
exposed the longest and had the driest soil (3S and 3N) 
(Table 5-25) . 

IVhen the data from both Spring and Rice lakes are con- 
sidered, two parameters that affect the growth of beggar- 
ticks are apparent: (1) beggar-ticks can grow in a wide 
range of soil moisture, and (2) early drawdown in most 
cases favors growth of beggar- ticks . 

Although no data on the productivity of beggar-ticks 
in the Illinois Valley is available, it is considered to 
be a fair waterfowl food. The small barbed achenes are 
consumed primarily by dabbling ducks and, to a lesser extent, 
diving ducks. 



Vegetation 

The Effects of Increased Diversion on Moist-Soil Plants 

The recession of river levels during the warm summer 
months exposes mud flats along the shores of bottomland lakes 
in the Illinois River valley. As soil conditions change, 
the germination requirements of different plant species 
are satisfied and thus moist-soil plants appear on the mud 
flats. Wet soil devoid of standing water is the primary 
requirement for germination of the majority of moist-soil 
plants. In addition to moist soil, this group of plants 
also requires an average of approximately 90 days to 
mature and produce seed. The period beginning 10 July 
and ending 1 October is considered to be the optimum for 
the growth and seed production of moist-soil plants before 
the first frost in fall. However, the sooner water levels 
recede in early summer, the greater the coverage of moist- 
soil plants in the lake basins of the Illinois Valley 
(Bellrose et al., 1979, in press). Moist-soil plants can 
withstand some degree of inundation. However, this 
tolerance varies among plant species and is dependent upon 
the maturity of the plants as well as the height that the 
basal structures of the plants are inundated. 

In order to investigate the effects of increased diver- 
sion on moist-soil plants, water level increases resulting 
from the proposed 6,600- and 10,000-cfs diversion were 
calculated for the 10 July-1 October growing season (Table 5-27) 
This was accomplished by determining the average water 
level increases for the growing season from the predicted 
results of the computer model provided by the Chicago 
District Army Corps of Engineers. These increases were 
calculated for three years of dissimilar water conditions, 
1971, 1973, and 1977. The increases predicted by the 
computer model were determined for one reference point in 
each pool. Henry was used as the reference point in 
Peoria Pool and Havana in La Grange Pool. These reference 
points were chosen because they are located near the 
middle of the Peoria and La Grange pools, respectively, 
and thus reflect the changes in water levels of these pools. 
The water level increases calculated from the computer 
model were then added to the average of the daily river 
gauge readings reported by the U.S. Weather Service for 
the 10 July-1 October growing season. The projected water 
level increases in msl (ft) for the 6,600- and the 10,000- 
cfs diversion that would have occurred at Henry and Havana 
during 1971, 1973, and 1977 are presented in Table 5-27. 

The abundance of mud flats in the Illinois River valley 
is regulated by the difference in elevation between low 
water levels and the tree line in the bottomland lakes -- 



5-90 ' 



Table 5-27. Average Gauge Readings in msl (ft) for Henry 

(Peoria Pool) and Havana (La Grange Pool) calcu- 
lated from the U.S. Weather Service River Stage 
Records with the Addition of the Increase in 
Water Levels as Predicted by the Computer Models 
for the 6,600- and 10,000-cfs Diversion. The 
Gauge Readings are for the Entire Growing Period 
of 10 July-1 October, 1971, 1973, and 1977. 



Year 



1971 



1973 



1977 



1971 



1973 



1977 



Average Gauge Average Gauge 
Average Reading Plus Reading Plus . 
Gauge Reading 6,600-cfs Diversion 1 , 000-cf s Divej 
msl (ft) msl (ft) msl (ft) '• 



Henry (Peoria Pool) 
440.9 441.9 



440.9 

I 



443.4 



4 41.6 
I 



-(2.5)- 

(1.7)- 
I 



(2.8). 



431 .9 



433.2 



(2.4)- 
(1.4)- 



434.3 
I 



434.6 

— ' ' (0.7) 

-(2.1) ' 



443.6 



(1,0)'' ' ' (1 .4) ' 

' (2.7) ^ 



443.3 444.4 
— " (1.1) ' 



Havana (La Grange Pool) 

430.9 432.3 433.5 

« (1.4) " (1.2) ' 

« (2.6) • 



435.3 
I 



Differences 



5-91 



Vegetation 



the lower the lake level, the greater the exposure of mud 
flats in the lake basin. Moist-soil plant development is 
governed by the duration of low water during the growing 
season. Small rises in water levels during the growing season 
may inundate and destroy extensive areas of moist-soil 
plants. The extent of mortality depends upon the height 
of the water rise and the lateness in the growing season. 
Once these plants are destroyed by a brief inundation, they 
may not have sufficient time to become re-established. 



Peor 

ms 1; 

seas 

leve 

and 

have 

ha ( 

Duri 

and 



The d 
ia Poo 

Henry 
on is 
Is for 
1975 i 

expos 
5,378, 
ng 197 
no mud 



istan 
1 and 

gaug 
only 

the 
n Peo 
ed be 
1 acr 
7, wa 

flat 



ce b 
the 
e) d 
0.34 
10 J 
ria 
twee 
es) 
ter 
s wo 



etwee 
lowe 
uring 
m (1 
uly-1 
Pool 
n 1,3 
of mu 
level 
uld h 



n the 
St ave 

the 1 
.1 ft) 

Octob 
wi thou 
62.4 h 
d flat 
s were 
ave be 



tree line ( 
rage water 
July-1 Oc 

(Table 5-27 
er growing 
t additiona 
a (3,366.5 
s (Tables 5- 

at the tre 
en exposed 



441 .6 ft, m 
level (440. 
tober growi 
) . Low wat 
season duri 
1 diversion 
acres) and 
21 5 5-27 ) 
e line (441 
(Table5-27) 



si) in 
5 ft, 

ng 
er 

ng 1971 
would 

2,176.5 

.6 ft) 



Water level increases in the Peoria Pool as a result 
of the proposed 6,600-cfs diversion would have raised 
water levels from 0.09 m (0.3 ft) to 0.55 m (1.8 ft) 
above the tree line during 1971, 1973, and 1977, thus 
completely inundating all of the mud flats (Table5-27). 
The 10,000-cfs diversion would have also flooded all of the 
mud flats by raising water levels 0.61 m (2.0 ft) and 0.85 
m (2.8 ft) above the tree line during 1971 and 1977, re- 
spectively (Table 5-27) . As a result of high water levels 
during 1 973 ,a 1 , 000- cf s diversion would not have been 
attained. 



The distance between the tree line (434.4 ft, msl) in 
La Grange Pool and the lowest average water level (430.4 ft, 
msl; Havana gauge) during the 10 July-1 October growing 
season is 1.22 m (4 ft) (Table 5-21). Low water levels for 
the 10 July-1 October growing season during 1971, 1973, 
and 1977 would have exposed approximately 10,466.5 ha 
(25,862.7 acres), 8,471.7 ha (20,933.6 acres), and 2,737.2 
ha (6,763.6 acres) of mud flats, respectively (Tables 
5-21 and 5-27) . 

Water level increases as a result of the 6,600-cfs 
diversion in 1971 in La Grange Pool would have reduced the 
area of mud flats by 61.41 and completely inundated all of 
the mud flats during 1973 and 1977 (Table5-27). The 
10,000-cfs diversion would have reduced the area of mud 
flats during 1971 by 73. 8S. In 1977, the 10,000-cfs 
diversion would have raised water levels 0.27 m (0.9 ft) 



5-92 



Vegetation 



above the tree line thereby completely inundating all mud 
flats in the La Grange Pool (Table 5-27 ) . Because of 
high water conditions, no 10,000-cfs diversion would have 
been attained during 1973. 

The lake basins of all the bottomland lakes in the 
Illinois Valley are extremely shallow (Chapter 4 ). 
Therefore^ small water level fluctuations may completely 
inundate mud flats during the summer growing season. 
Because of the small difference between the tree line 
and the low water level in Peoria Pool (0.34 m; 1.1 ft), 
the 6,600-cfs diversion would have completely destroyed 
moist-soil plants on the mud flats during all three 
study years. The 10,000-cfs diversion would have been 
several feet above the tree line, thus inundating large 
areas of bottomland forest as well as the mud flats in 
Peoria Pool. 

There is a greater difference in elevation between 
the low water level and the tree line (1.22 m; 4.0 ft) 
in La Grange Pool. During 1971, mud flats would have 
still been exposed despite increased water levels 
resulting from the proposed 6,600- and 10,000-cfs 
diversions. However, no mud flats would have appeared 
during 1973 and 1977. 



6-1 



CHAPTER 6 : WATERFOWL HUNTING AREAS 



The Illinois River valley is one of the nation's most 
important areas for migrating waterfowl. Long ago, hunters 
recognized the abundance of vaterfowl in the bottomland lakes 
of the valley and in the 1890's sportsmen began to acquire 
bottomland property for the purpose of forming "duck clubs". 
However, the prohibition of baiting in the mid-1930's greatly 
reduced the duck kill by private clubs in the Illinois Val- 
ley (Bellrose, 1944: 368). Although the navigation dams 
built on the Illinois River in the late 1930's increased 
the natural food resources for vaterfowl, it became neces- 
sary for duck clubs to control water levels on their pro- 
perty in order to maintain high quality hunting. Water 
levels are manipulated on many private duck clubs and 
public waterfowl areas. Water manipulation permits duck 
food plants to be sown or volunteer on mud flats during the 
summer and then allows them to be flooded with water during 
the fall for attraction of migrating waterfowl. By 1941, 
432 (55i>) of the 792 duck clubs in Illinois were located 
in the Illinois Valley (Bellrose, 1944: 16). During the late 
1950's and early 1960's, thousands of acres of aquatic duck 
food plants were lost in the valley as increasing sedimen- 
tation and turbidity filled shallow productive areas and 
clouded the waters of the bottomland lakes. As a result 
of this degradation, the management of water levels by duck 
clubs and state and federal agencies is now almost mandatory 
if high quality hunting is to be enjoyed. 

The Illinois Department of Conservation issued licenses 
to 272 private duck hunting clubs that managed land along 
the Illinois River during 1977 (Tables 6-1 5 D- 1 J. Other waterfowl 
clubs that did not receive a license may exist along the 
river. Howeverj this report is based on information from 
only these 272 licensed clubs. Peoria (11,129 ha; 27,499 
acres) and La Grange pools (12,371 ha; 30,569 acres) contain 
87.3°6 of the total 26,905 ha (66,482 acres) controlled by 
licensed duck clubs in the Illinois Valley (Table 6-1), 
primarily because of the numerous bottomland lakes and 
sloughs in these pools. 



6-2 



Table 6-1. Total Hectares (Acres) and Number of Duck Clubs 
Bordering the Illinois River by Counties, 1977^, 



County 



Cook 
Du Page 
Kill 
Grundy 

Total 



La Salle 

Bureau 

Putnam 

Marshall 

Woodford 

Peoria 

Total 



Tazewel 1 

Fulton 

Mason 

Schuyler 

Cass 

Total 



Brown 

Morgan 

Pike 

Scott 

Greene 

Calhoun 

Total 

Total, All Pools 272 



No. of 
Clubs 




Total Area 




Hectares 




Upper 


Pools 


1 




60.7 


3 




50.2 


10 




431 .4 


6 




1,726.0 


20 




2,268.3 




Peoria Pool 


18 




1 ,035.6 


30 




1,233.5 


29 




3,055.8 


38 




3,414.0 


26 




1,649.9 


6 




739.8 


147 




11 ,128.6 




La Grange Pool 



1 
7 

62 
2 

21 


47.8 
620.8 

8,663.7 
502.7 

2,536.0 


93 


12,371.0 




Alton Pool 


1 
3 
1 

2 
4 

1 


85.0 
350.5 

35.2 

15.0 
599.0 

52.2 


12 


1,136.9 


72 


26,904.8 



Acres 



150.0 

124.0 

1 ,066.0 

4,265.0 

5,605.0 



2,559.0 
3,048.0 
7,551.0 
8,436.0 
4,077.0 
1 ,828.0 

27,499.0 



118 

1 ,534 

21 ,408 

1 ,241 

6,268 

30,569 





210 




866 




87 




37 


1 


,480 




129 


2 


,809.0 


66 


,482.0 



Not all of the duck clubs listed are directly affected by 
the Illinois River. 



6-3 
Areas 



In September, 1978, a questionnaire was sent to 219 of 
the duck clubs that owned 16 hectares (40 acres) or more along 
the Illinois River, A total of 160 (73.1-0) of the clubs 
responded, representing 77,31 (20,803 ha; 51,405 acres) 
of the total area managed by licensed duck clubs in the 
Illinois Valley (Table 6-2). Water levels could be con- 
trolled on almost 326 (6,603 ha; 16,315 acres) of the total 
area managed by the clubs responding to the questionnaire 
(Table 6-2). The clubs in La Grange and Peoria pools ac- 
counted for 97.8b of the area under water level management. 

The U.S. Fish and Wildlife Service and the Illinois 
Department of Conservation own 20,428 hectares (50,478 
acres) in the Illinois River valley containing 9,853 hec- 
tares (24,344 acres) of water (Table 6-3). Water levels 
can be managed on 14.6^o (2,990 ha; 7,388 acres) of the 
total area. La Grange Pool has the greatest number of 
state and federal hectares with water level control. 

In addition to impoundments where water levels can be 
controlled, thousands of hectares of publicly- and privately- 
owned waterfowl areas rely on naturally occurring low water 
levels during the summer for the establishment of moist- 
soil vegetation and the planting of agricultural duck foods. 
Also, sections of federal, state, and private duck-hunting 
lands are refuge or "rest" areas where no hunting and 
little disturbance is permitted during the waterfowl 
season. 



The water area on state and federal properties C2-^8^.3 -^""^ 
haX anT the total area of licensed private duck clubs (26,905 
ha) comprise about 36,758 ha (90,829.0 acres) that are used 
primarily for waterfowl hunting and management, representing 
approximately 43,21, of the 85,020 ha (210,000 acres) of , | ^ 9^ 3 
nonleveed floodplain in the Illinois Valley. About 76,923- "4^2-3 
ITa (190,000 acres) of the 161,943 ha (400,000 acres) in the - .., j 
floodplain are in levee and drainage districts primarily ^^ -^ 
for agricultural purposes (Mulvihill and Cornish, 1930: 38). 

Natural or moist-soil duck foods (see the moist-soil 
vegetation section, page 5-66) volunteer on mud flats ex- 
posed by low water levels during the summer. Of the private 
clubs responding to our questionnaire that control water 
levels, an average of 18.0b managed exclusively for natural 
food plants, whereas 24.0b managed for agricultural crops 
(Table 6-2). Both natural and agricultural foods manage- 
ment occurred on an average of 58.0b of the private clubs 
with water level control (Table 6-2). Japanese millet was 
the most common agricultural crop planted by private duck 
clubs (59.01,) followed by buckwheat (58.01), corn (46.01), 
soybeans (2-01), rice (1.01), and milo (1.01). State and 



6-4 



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Areas 



federal agencies planted primarily Japanese inillet, corn, 
and buckwheat. Although Japanese millet can be broadcasted 
on mud flats, conventional planting methods are used for 
the other agricultural crops. It is imperative that areas 
devoted to agricultural crops be dewatered early in the 
growing season (May-June) to permit the ground to dry in 
order to operate farm machinery. 



EFFECTS OF INCREASED DIVERSION 



The approximate height of the levees and control 
structures on private duck clubs and public waterfowl areas 
was obtained from the duck club questionnaire and by 
contacting state and federal refuge personnel. To evaluate 
possible overtopping of these levees resulting from in- 
creased diversion predicted by the computer models for the 
Henry and Havana gauges, the heights of the levees and 
control structures at the private and public areas were 
adjusted to central ly- located reference points in each 
pool to compensate for the fall of the river. In the 
Peoria Pool, the levee heights were adjusted to the Henry 
gauge and those in the La Grange Pool were adjusted to the 
Havana gauge, the same gauges used in the computer models. 
These adjustments were made using stage duration curves of 
the river for the span of years from 1940 to 1973 for the 
Henry or Havana gauge and the gauge nearest the duck club 
or private area. On the stage duration curves for the 
reference gauge (Henry or Havana) and the gauge nearest 
the waterfowl area in question, the difference between the 
median water levels (the level where the water surface was 
above or below 501 of the time) was determined. This 
difference was divided by the distance between the same 
two gauges to derive the fall of the river per mile. Then 
the distance between the waterfowl area and the reference 
gauge was multiplied by the fall per mile to calculate 
their difference in elevation. This difference in eleva- 
tion was added to the height of the levee at the waterfowl 
area if it was downstream of the reference gauge and 
subtracted if it was upstream. The water surface at the 
50°o level on each stage duration curve was used because 
it approximates the average water level in the Peoria or 
La Grange Pool. 

The number of hectares of private duck clubs in the 
Peoria Pool and private and public land in the La Grange 
Pool with the amount that would be inundated at various 
river levels are presented in Tables 6-4 , 6-5 , and 6-6 . 
The number of hectares of state and federal lands under 
water level management in the Alton Pool and the heights 
of their respective levees are listed in Table 6-7. 



6-7 



Table 6-4, The Number of Hectares (Acres) of Private Duck 

Clubs with Water Control that would be Inundated 
at the Various Respective River Levels in the 
Peoria Pool. 





Henry G 


auge 




No . 


f 


Cumulative No. of 


msl 


Ac 


tual Reading 
m ft 


Hectares 
ha 


(Acres) 
acres 


Hectares 
ha 


(Acres) 


m 


ft 


acres 


134.44 


441 .1 


3.63 


11.9 










134.60 


441 .6 


3.77 


12.4 










134.75 


442.1 


3.93 


12.9 


16.2 


40 


16.2 


40 


134.90 


442.6 


4.08 


13.4 


26.7 


66 


42.9 


106 


135.06 


443.1 


4.24 


13.9 


59.9 


148 


102.8 


254 


135.20 


443.6 


4.39 


14.4 


176.0 


435 


278.8 


689 


135.45 


444.1 


4.54 


14.9 


201 .5 


498 


480.4 


1 ,187 


135.51 


444.6 


4.69 


15.4 


230.7 


570 


711 .0 


1 ,757 


135.66 


445.1 


4.85 


15.9 


205.6 


508 


916.6 


2,265 


135.82 


445.6 


5. on 


16.4 










135.97 


446.1 


5.15 


16.9 


914.6 


2,260 


1,831 .2 


4,525 


136.12 


446.6 


5.30 


17.4 










136.27 


447.1 


5.46 


17.9 


374.7 


926 


2,206.0 


5,451 


136.42 


447.6 


5.61 


18.4 










136.58 


448.1 


5.76 


18.9 


85.0 


210 


2,291 .0 


5,661 


136.73 


448.6 


5.91 


19.4 










136.88 


449.1 


6.07 


19.9 


12.1 


30 


2,303.1 


5,691 


137.05 


449.6 


6.22 


20.4 










137. 19 


450.1 


6.37 


20.9 










137.34 


450.6 


6.52 


21.4 










137.50 


451 .1 


6.68 


21 .9 


24.3 


60^ 


2,327.4 


5,751 



Douglas Lake area. 



6-8 



Table 6-5. The Number of Hectares (Acres) of Private Duck 

Clubs with Water Control that would be Inundated 
at the Various Respective River Levels in the 
La Grange Pool. 



H 


avana Gauge 




No. o: 
Hectares 

ha 


f 
(Acres) 

acres 


PlimillPt"1\7P \] r\ j-i-F 


ms 


1 Act 


ual Reading 
m ft 


Hectares 
ha 


(Acres) 


m 


ft 


acres 


131 .46 


431.3 


2.13 


7.0 


16.2 


40 


16.2 


40 


131.61 


431 .8 


2.29 


7.5 










131 .77 


432.3 


2.44 


8.0 










131 .92 


432.8 


2.59 


8.5 


34.4 


85 


50.6 


125 


132.07 


433.3 


2.74 


9.0 


144.5 


357 


195.1 


482 


132.22 


433.8 


2.90 


9.5 


36.4 


90 


231 .5 


572 


132.37 


434.3 


3.05 


10.0 


103.2 


255 


334.7 


827 


132.53 


434.8 


3.20 


10.5 


14.2 


35 


348.9 


862 


132.68 


435.3 


3.35 


11.0 


182.1 


450 


531 .0 


1 ,312 


132.83 


435.8 


3.51 


11.5 


8.1 


20 


539.1 


1 ,332 


132.98 


436.3 


3.66 


12.0 


886.3 


2,190 


1,425.4 


3,522 


133.14 


436.8 


3.81 


12.5 










133.29 


437.3 


3.96 


13.0 


233.9 


578 


1 ,659.3 


4,100 


133.44 


437.8 


4.11 


13.5 


1,214.1 


3,000 


2,873.4 


7,100 


133.59 


438.3 


4.27 


14.0 


40.5 


100 


2,913.9 


7,200 


133.75 


438.8 


4.42 


14.5 


40. S 


100 


2,954.4 


7,300 


133.90 


439.3 


4.57 


15.0 


26.3 


65 


2,980.2 


7,365 


134.05 


439.8 


4.72 


15.5 










134.20 


440.3 


4.88 


16.0 


222.6 


550 


3,203.3 


7,915 


134.36 


440.8 


5.03 


16.5 










134.51 


441.3 


5.18 


17.0 


163.9 


405 


3,367.2 


8,320 


134.66 


441 .8 


5.33 


17.5 










134.81 


442.3 


5.49 


18.0 


174.0 


430 


3,541 .2 


8,750 


134.97 


442.8 


5.64 


18.5 










135.12 


443.3 


5.79 


19.0 










135.27 


443.8 


5.94 


19.5 










135.42 


444.3 


6.10 


20.0 


32.4 


80 


3,573.6 


8,830 


135.58 


444.8 


6.25 


20.5 










135.72 


445.3 


6.40 


21.0 










135.88 


445.8 


6.55 


21 .5 










136.03 


446.3 


6.71 


22.0 











6-9 



Table 6-6. The Number of Hectares (Acres) Under Water Control 
by the U.S. Fish and Wildlife Service and the 
Illinois Department of Conservation^ that Would Be 
Inundated at the Various Respective Water Levels 
in La Grange Pool. 



H 


avana G 


auge 




No. of 
Hectares (Acres) 

ha acres 


Cumulative 
Hectares 

ha 


No. of 


ms 


1 Ac 


tual Reading 
m ft 


(Acres) 


m 


ft 


acres 


131 .46 


431 .3 


2.13 


7.0 












131.61 


431 .8 


2.29 


7.5 












131 .77 


432.3 


2.44 


8.0 












131.92 


432.8 


2.59 


8.5 












132.07 


433.3 


2.74 


9.0 












132.22 


433.8 


2.90 


9.5 












132.37 


434.3 


3.05 


10.0 












132.53 


434.8 


3.20 


10.5 












132.68 


435.3 


3.35 


11 .0 


413.4 


1,021. 


.5 


413.4 


1 ,021 .5 


132.83 


435.8 


3.51 


11 .5 












132.98 


436.3 


3.66 


12.0 












133.14 


436.8 


3.81 


12.5 












133.29 


437.3 


3.96 


13.0 


248.9 


615, 


.0 


662.3 


1 ,636.5 


133.44 


437.8 


4.11 


13.5 












153.59 


438.3 


4.27 


14.0 


436.2 


1 ,078. 


.0 


1 ,098.5 


2,714.5 


133.75 


438.8 


4.42 


14.5 












133.90 


439.3 


4.57 


15.0 


182.4 


450, 


.0 


1,280.9 


3,164.5 


134.05 


439.8 


4.72 


15.5 












134.20 


440.3 


4.88 


16.0 












134.36 


440.8 


5.03 


16.5 












134.51 


441 .3 


5.18 


17.0 












134.66 


441 .8 


5.33 


17.5 












134.81 


442.3 


5.49 


18.0 


80.1 


198. 


.0 


1 ,361 .0 


3,362.5 


134.97 


442.8 


5.64 


18.5 












135.12 


443.3 


5.79 


19.0 


44.1 


109. 


.0 


1,405.1 


3,471.5 


135.27 


443.8 


5.94 


19.5 












135.42 


444.3 


6.10 


20.0 












135.58 


444.8 


6.25 


20.5 












135.72 


445.3 


6.40 


21 .0 












135.88 


445.8 


6.55 


21 .5 


414.5 


1,024. 


.2 


1,819.6 


4,495.7 


136.03 


446.3 


6.71 


22.0 












136. 18 


446.8 


6.86 


22.5 












136.34 


447.3 


7.01 


23.0 












136.50 


447.8 


7.16 


23.5 












136.64 


448.3 


7.32 


24.0 












136.79 


448.8 


7.47 


24.5 












136.95 


449.3 


7.62 


25.0 


2.0 


5, 


,0 


1,821 .6 


4,500.7 


137.10 


449.8 


7.77 


25.5 













State-owned Spring Lake is behind a major levee in Spring Lake 
Drainage and Levee District and therefore not included. 



6-10 



Table 6-7. The Number of Hectares (Acres) of State and Federal 
Lands with Water Control in the Alton Pool and 
the Heights of Their Respective Levees. 



Area 



Si ze 



Height of 
Levees, insl 



State/ _ _ 

Federal 
Ownership Hectares Acres Meters Feet 



Meredosia' 



30.6 75.7 



Godar 



115.4 285.0 



128.3 421 .0 



Diamond 



Glades 



12 Mile Island 



Fuller Lake 



Stump Lake 



Calhoun Point 



Calhoun Unit 



111.3 275.0 



108.9 269.0 



2.4 



6.0 



91 . 1 225.0 



182.1 450.0 



141.6 350.0 



74.9 185.0 



128.6 
128.6 
129.2 
128.6 
128.3 
128.3 
128.9 



422.0 
422.0 
424.0 
422.0 
421 .0 
421 .0 
423.0 



Total 



:58 2,120.8 



The levee height of federal ly- owned Lake Meredosia could not 
be obtained. 



6-11 
Areas 



The computer models for the increased diversion rates 
were used to evaluate the amount of private and public 
waterfowl areas that would be inundated during the 10 July- 
1 October growing season (the minimum time period for 
moist-soil plants to become established and produce seed) 
by comparing the levee heights of the waterfowl impoundments 
to predicted water levels. The actual average river level 
at Henry and Havana for this entire growing season was 
calculated from U.S. Weather Service river stage records 
for 1971, 1973, and 1977. To these actual river levels 
we added the average rise in water levels for this growing 
season that would have occurred, as predicted by the 
computer models, if the 6,600- and 10,000-cfs diversion 
took place during these three years (Table 5-27). We 
then compared these water levels (the actual average 
plus the increase from the proposed diversions) to the 
levee heights of the waterfowl areas to determine if over- 
topping would have occurred. 



Peoria Pool 

Levee heights of private duck clubs responding to our 
questionnaire in the Peoria Pool were reported for 2,327 ha 
(5,751 acres) (Table 6-4). The only publicly controlled 
water management area in the Peoria Pool is the 10.1-ha 
(25.0-acre) impoundment at the mouth of Lake De Pue. 

The average river levels calculated for the 10 July- 
1 October period at Henry were 440.9, 440.9, and 441.6 
msl in 1971, 1973, and 1977, respectively (Table 5-27) . 
These naturally occurring levels would not have overtopped 
any of the reported duck clubs' levees (Table 6-4). 

The projected 6,600-cfs diversion would have increased 
the water levels for the 10 July-1 October period during 
1971, 1973, and 1977 to 441.9, 443.4, and 443.3 msl, respec- 
tively (Table 5-27). None of the area of responding duck 
clubs in the Peoria Pool would have been inundated by this 
increase during 1971. In 1973 and 1977, 4.41 (103 ha; 
254 acres) of leveed duck club area would have been flooded 
(Table 6-4 ) . 

The projected 10,000-cfs diversion would have increased 
the water levels for the 10 July-1 October growing season 
to 443.6 and 444.4 msl during 1971 and 1977 (Table 5-27). 
High water during 1973 would have prohibited a 10,000-cfs 
diversion. These increased water levels during 1971 and 1977 
would have inundated approximately 12.0°i (279 ha; 689 acres) 



6-12 



Areas 



and 20.61. (480 ha; 1,187 acres), respectively, of the leveed 
area of the responding duck clubs in the Peoria Pool (Table 
6-4) . 



La Grange Pool 

Duck clubs responding to our questionnaire reported 
levee heights for 3,574 ha (8,830 acres) in the La Grange 
Pool (Table 6-5). The average water levels for the 10 
July-1 October growing season at Havana during 1971, 1973, 
and 1977 were 430.9, 431.9, and 433.2 msl, respectively 
(Table 5-27) . Natural water levels during 1971 would not 
have overtopped any control levees in the La Grange Pool 
(Table 6-5). However, during 1973, 0.41 (16 ha; 40 acres) 
of the leveed land of responding private duck clubs would 
have been flooded and 1.41, (51 ha; 125 acres) would have 
been inundated in 1977 (Table 6-5 ). 

The projected 6,600-cfs diversion at Havana would have 
raised water levels to 432.3, 434.3, and 434.6 msl during 
1971, 1973, and 1977, respectively (Table5-27). This in- 
creased diversion would have inundated 0.41 (16 ha; 40 
acres) during 1971, and 9.41, (335 ha; 827 acres) during 1973 
and 1977 of the leveed land of responding duck clubs in the 
La Grange Pool (Table 6-5). No state or federal land would 
have been flooded (Table 6-6) . 

The projected 10,000-cfs diversion would have raised 
water levels at Havana to 433.5 and 435.3 msl during 1971 
and 1977 (Table 5-27). Because of high water conditions 
during 1973, the 10,000-cfs diversion would not have oc- 
curred. During 1971, the increase would have inundated a 
total of 5.5° (195 ha; 482 acres) of the leveed private 
duck club land, 5.01 (179 ha; 442 acres) more than the 
6,600-cfs diversion (Table 6-5). A 10,000-cfs diversion 
during 1977 would have flooded 5.51 (196 ha; 484 acres) 
more than the 6,600-cfs diversion resulting in a total of 
14.91, (531 ha; 1,312 acres) of the land belonging to duck 
clubs that responded to our questionnaire being flooded 
(Table 6-5). In addition, the 10,000-cfs diversion would 
have inundated 22.71, (413 ha; 1,022 acres) of state and 
federal property (Table 6-6 ) . A total of 17.51> (944 ha; 
2,332 acres) of land with water level management programs 
in La Grange Pool would have been flooded during 1977 as a 
result of the 10,000-cfs diversion. 



6-13 



Areas 



Alton Pool 

In the Alton Pool, 858 ha (2,121 acres) of state and 
federal land (Tables 6-3 ,6-7 ) and 126 ha (311 acres) 
(Table 6-2; belonging to private duck clubs responding to 
our questionnaire were capable of managing water levels. 
Computer models for increased diversion were not evaluated 
for the Alton Pool. Thus, the overtopping of levees on 
private waterfowl areas by increased diversion was not 
investigated. Low pool level at Alton, Illinois is approxi 
mately 419.0 msl. The height of 99.71 of the levees at 
publicly-owned areas (Table 6-7 ) will keep out a water 
level increase of approximately 1 m (2 to 3 ft) above 419.0 
msl. Therefore, if increased diversion would result in a 
water level rise of more than 1 m (3 ft) , these public 
areas would be inundated. 



All Pools 

In addition to the flooding of leveed waterfowl im- 
poundments, higher water levels from increased diversion 
could adversely affect leveed areas in other ways. Approxi 
mately 63S of the private duck clubs that answered our 
questionnaire rely on natural conditions to both expose 
mud flats during the growing season for moist-soil plants 
(10 July-1 October) and then reflood them during early fall 
for duck hunting. As a result of increased diversion, 
higher water levels could impede the flow of water out of 
these areas making it impossible to achieve a drawdown. 
Reflooding can be accomplished by (1) allowing naturally 
occurring high river levels to enter the impoundments 
through control structures, (2) preventing the flow of 
spring waters out of impoundments, or (3) diverting creek 
water into the impoundments. 

The remaining clubs (38°o) employ either diesel or 
electric pumps to move water in and out of impoundments. 
Higher water levels could greatly increase pumping costs 
and, in some cases, because of seepage, may make it im- 
possible to pump impoundments dry enough for the establish- 
ment of moist-soil plants. Wave action during high water 
levels would greatly increase the erosion of earthen levees 
surrounding duck clubs. In order to build these levees 
higher, the bases of the levees must be widened to support 
the greater height. The construction of such levees takes 
between 2 to 3 years because the levees must be built in 
stages to allow the mud to dry and compact. 



6-14 



Areas 



The rising costs of land prices, energy for pumps, 
agricultural equipment, maintenance of club houses, and in 
some cases, salaries for caretakers and assistants, have 
been responsible for an increase in membership fees of 
private duck clubs. Some of the more affluent clubs re- 
quire a large initiation fee plus yearly membership dues 
of several hundred dollars. The cost of bagging a duck by 
a member at many clubs has been estimated to be in excess of 
$100. 

Waterfowl hunters represent one of the largest private 
interests in the Illinois Valley. Economic consideration 
needs to be given to state, federal, and private land 
managed for waterfowl hunting. To reduce potential ad- 
verse effects of increased diversion on waterfowl hunting 
areas or to provide mitigation for other possible detri- 
mental effects caused by increased diversion, the following 
measures could be implemented: 

1. Maintain natural low water levels during the 

10 July-1 October growing season to allow waterfowl food 
plants to become established and produce seed. 

2. Finance the building of larger or new levees and 
defray subsequent increased pumping costs if water levels 
remain high during July through October because of in- 
creased diversion. 

3. Provide reimbursement for levee damages, loss 
of hunting area, or reduced hunting success resulting 
from higher water levels of increased diversion. 



7-1 



CHAPTER 7 : KATERFOU'L POPULATIONS 



Waterfowl frequent the Illinois River valley throughout 
the year but they are most abundant in the fall and next 
most abundant in the spring. At times several hundred 
thousand mallards ( Anas platyrhynchos ) winter in the valley 
along with hundreds of common goldeneyes ( Bucepha la clangula ) 
and common mergansers ( Mergus merganser ) . Wood ducks ( Aix 
sponsa ) breed more abundantly along the backwater lakes than 
elsewhere in the state; indeed the Illinois Valley is one of 
the most important breeding grounds for this species in the 
nation . 

As many as 32 species of waterfowl visit the water, 
areas of the Illinois River; however, only 20 species are 
of regular occurrence. Dabbling ducks are much more abun- 
dant than diving ducks during the fall, less so during the 
spring (Tables /-I and ^"2 ) . By far the most abundant 
species is the mallard, composing an average of 80.60 of the 
fall population, 1976-1978 (Table 7-3) and43.3°6of the 
spring population, 1977-1979 (Table 7-4 ). 

The fall migration period extends from early August, 
with the appearance of a few thousand blue-winged teal 
( Anas discors ) , and usually ends in mid-December, with 
the departure of the bulk of the mallards. Within the time 
frame 1 October-2 December, 1976-1978, we made weekly 
aerial estimates of the number of waterfowl by species in 
the Illinois Valley. Weekly aerial censuses were also 
made in the spring, but only once during mid-winter. 

A comparison of the abundance of waterfowl during the 
fall in the navigation pools is shown in Table 7-1 . The 
population data in Tables 7-H 7-2 are expressed in waterfowl 
use-days (one bird present one day forms a use-day) and 
use-days per hectare of water surface for the fall and spring 
periods . 

During the fall, 1976-1978, there was an average of 
39,153,293 use-days by ducks and geese; dabbling ducks com- 
posed 92.3?,, diving ducks 2.9'o, and geese 4.81. Coots 
( Fulica americana ) , which are not true waterfowl but 
are ecologically similar, averaged 5,750,535 use-days (Table 7-1) 



7-2 



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7-4 



Table 7-5 . Percent Species Composition of the Fall Waterfowl 
Populations in the Illinois River Valley, 1976-1971 



Species 


1976 


1977 


1978 


Average 


Lesser snow goose 


1 .87 


1 .55 


2.95 


2.12 


Canada goose 


2.07 


2.52 


2.95 


2.51 


American wigeon 


5.74 


5.62 


8.07 


5.81 


Gadwall 


0.20 


0.45 


0.41 


0.55 


Green-winged teal 


1 .42 


0.71 


1 .21 


1.11 


Mallard 


85.15 


80.92 


75.80 


80.62 


Black duck 


1 .54 


1 .44 


1 .55 


1 .57 


Pintail 


2.05 


2.90 


5.28 


2.74 


Blue-winged teal 


0.72 


0.55 


0.66 


0.57 


Shoveler 


0.14 


0.10 


0.01 


0.08 


Canvasback 


0.08 


0.46 


0.40 


0.51 


Redhead 


0.00 


0.09 


0. 10 


0.06 


Ring-necked duck 


0.24 


0.66 


0.65 


0.51 


Lesser scaup 


0.64 


1 .59 


1 .42 


1 .22 


Bufflehead 


0.00 


0.02 


0.17 


0.06 


Common goldeneye 


0.24 


0.58 


0.40 


0.54 


Hooded merganser 


0.01 


0.01 


0.02 


0.01 


Red-breasted merganser 


0.00 


trace 


0.00 


trace 


Common merganser 


0.08 


0. 17 


0.15 


0.15 


Ruddy duck 


0.05 


0.10 


0.08 


0.08 



Total 100.00 100.00 100.00 100.00 



7-5 



Table 7-4. Percent Species Composition of the Spring Waterfowl 
Populations in the Illinois River Valley, 1977-1979 



Species 

Lesser snow goose 

Canada goose 

American wigeon 

Gadwall 

Green-winged teal 

Mallard 

Black duck 

Pintail 

Blue-winged teal 

Shoveler 

Canvasback 

Redhead 

Ring-necked duck 

Lesser scaup 

Bufflehead 

Common goldeneye 

Hooded merganser 

Red-breasted merganser 

Common merganser 

Ruddy duck 

Total 



1977 


1978 


1979 


Average 


0.86 


0.87 


0.98 


0.90 


6.56 


6.04 


7.17 


6.53 


7.07 


5.01 


8.86 


6.98 


0.60 


0.15 


0.81 


0.52 


1 .90 


0.58 


0.78 


1 .09 


58.69 


36.18 


35.00 


43.29 


1 .41 


0.69 


0.69 


0.93 


5.59 


1 .25 


3.01 


3.28 


3.75 


0.71 


1 .88 


2.12 


1 .13 


0.66 


1 .48 


1 .09 


2.22 


2.15 


3.38 


2.58 


0.25 


0.41 


0.70 


0.45 


4.27 


9.41 


10.50 


8.06 


4.78 


34.76 


21 .04 


20.19 


0.00 


0.00 


0.02 


0.01 


0.71 


0.77 


2.66 


1 .38 


trace 


0.00 


0.00 


trace 


0.00 


0.00 


0.00 


0.00 


0.20 


0.19 


0.75 


0.38 


0.21 


0.17 


0.29 


0.22 


00.00 


100.00 


100.00 


100.00 



7-6 



Waterfowl Populations 



A hectare of water in the Illin 
fall provided an average day of use 
196 coots (Table 7-1). The number 
per hectare was greatest in 1976 an 
of the La Grange Pool, followed by t 
Pool, and lastly the Upper Pools (T 
1978, dabbling and diving ducks wer 
per hectare of water in the Alton P 
Grange, Peoria, and Upper Pools. G 
in the Alton Pool, then the La Gran 
The relative abundance of coots per 
navigation pools increased apprecia 



ois Valley during the 

for 1,337 waterfowl and 
of dabbling and diving ducks 
d 1977 in backwater lakes 
he Alton Pool, the Peoria 
able 7-1; Figure 3-1). In - 
e slightly more abundant 
ool followed by the La 
eese were most abundant 
ge, Peoria, and Upper Pools, 
hectare among the several 
bly from north to south. 



During the spring migration, the hectare density of 
both dabbling and diving ducks and geese was usually greatest 
in the La Grange Pool, followed by the Alton and Peoria navi- 
gation pools (Table 7-2). However, the most geese occurred 
in the Peoria Pool in 1978 and the most diving ducks occurred 
in the Alton Pool in 1979 (Table 7-2). The upper navigation 
pools were not censused during the spring. 

A comparison of the waterfowl day use between fall and 
spring emphasizes the greater importance of the Illinois 
Valley to many species during the fall. Dabbling duck use 
was almost four times greater during the fall in the three 
lower pools (Tables 7-1 and 7-2). However, a comparatively 
small population of diving ducks was 5 times more abundant 
during the spring than the fall. The two species of geese 
were twice as abundant in the fall as in the spring, largely 
because of the numbers of lesser snow geese ( Anser caerulescens ' 
in the fall. Most of these geese miss Illinois m the 
spring, migrating north up the Missouri River. 

The winter periods were construed as extending from 2 
December 1976 to 9 March 1977, 2 December 1977 to 23 March 
1978, and 2 December 1978 to 16 March 1979, depending upon 
the first waterfowl census in the spring (Table 7-5). Al- 
though only one aerial census was made during each winter 
period, it probably was a representative approximation of 
populations for the period. Other field observations indicate 
that waterfowl decline from early December to late February, 
when the spring migration commences. The January census is 
in about the middle of this time span. 

An average of 1 6 , 8 75 , 8 1 8 waterfowl use-days occurred 
during the last three winters (1976-77, 1977-78, 1978-79) 
(Table 7-5) . Mallards composed 85. 4S of all wintering birds, 
goldeneyes 6.31,, Canada geese ( Branta canadensis ) 3.21, 
black ducks ( Anas rubripes ) 2.1 I , common mergansers 2.0 1. 
and others 1.0°. Winter inventories taken over a period of 
25 years disclose that numbers of ducks during the last 



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7-10 



Waterfowl Populations 



three years are below normal. This appears to be related to 
the unusually severe weather that has prevailed. 

It is evident that there are some major differences 
between the fall and spring composition of waterfowl popu- 
lations (Tables 7-1 and 7-2). Mallard use-days are much 
lower in the spring, apparently because they migrate north- 
ward at an accelerated rate (Bellrose, 1976: 238-239). 
Among the dabblers, pintails ( Anas acuta ) , blue-winged 
teals, and shovelers ( Anas clypeata ] are more numerous in 
the spring than the fall. All the bay diving ducks (can- 
vasback ( Aythya valisineria ) , redhead (A. americana ) , 
ring-necked duck (A. collaris ) , and lesser scaup (A. aff inis )) 
are at least 8 times more abundant in the spring. High 
water provides new habitat and food supplies during the 
spring that enable diving ducks to occur in greater numbers. 



EFFECT OF FOOD RESOURCES ON WATERFOWL POPULATIONS 



Over a period of 40 years, Bellrose has observed a 
local and a valley-wide effect of food resources on water- 
fowl populations. Data to quantify these observations were 
difficult to obtain because of the lack of manpower to 
document the yearly food resources in a desired detailed 
fashion. However, the data that we do have indicate the 
importance of summer and fall water levels on the produc- 
tion and availability of duck food plants, and in turn their 
effect upon fall duck populations. 

Aquatic plants have virtually disappeared from the 
backwater lakes of the Illinois Valley as a result of sedi- 
mentation (Bellrose et al., 1979). The increasing accumu- 
lation of sediments has resulted in increased turbidity 
through the agency of waves and fish that readily resus- 
pend the flocculent bottom materials (Jackson and Starrett, 
1959). Marsh plants, especially those that produce seed 
for waterfowl food, have also greatly declined (Bellrose 
et al. , 1977) . 

Thus during the last two decades and into the fore- 
seeable future, moist-soil plants have assumed and will play 
increasingly important roles in the duck food resources of 
the Illinois Valley. As discussed in detail elsewhere (see 
Moist-soil Plants, page 5-66) , the development of 
moist-soil plants depends upon the extent and period of 
mud flat exposure in midsummer. Moreover, waterfowl use 
of seeds produced by moist-soil plants is related to fall 
water levels. 



7-n 

Waterfowl Populations 



In an earlier study, Bellrose et al. (1979) found that 
the abundance of certain species of waterfowl was correlated 
with the availability of native food resources. Among 
dabbling duclcs , the size of fall populations of mallards, 
pintails, green-winged teals ( Anas crecca carolinensis ) , 
and wigeons (A, americana) was related to the occurrence of 
wetland plants. Diving duck numbers were not correlated 
with the wetland plant abundance. Their populations catas- 
trophically decreased in the mid-1950's following the dis- 
appearance of fingernail clams from the waters of the 
Illinois Valley (Mills et al., 1966). For unknown reasons, 
fingernail clams have not recovered. Correspondingly, 
diving duck numbers have not regained their former abundance. 

River levels during the fall determine the depths of 
bottomland lakes, and, consequently, to a degree, the 
availability of moist-soil plant seeds. As discussed more 
fully elsewhere (see Chapter 6 , Waterfowl Hunting Areas, 
page 6-1), about one-third of the water areas within the 
floodplain are subject to low water management by private 
duck clubs, state and federal conservation agencies. Con- 
structed low levees prevent small rises in the river level 
from inundating moist-soil plant beds. These shallow im- 
poundments are flooded during the fall by a foot or more of 
water provided by springs or pumping to make the moist- 
soil plant seeds available to waterfowl. 

Because at the present time about two-thirds of the 
hectares of lake basins are not protected by small levees, 
their le -els are regulated entirely by that of the river. 
A decline in water levels during the summer followed by a 
slight rise during the fall is advantageous to waterfowl. 
Figure 4-2 shows that the "normal" seasonal change in river 
levels almost follows this regime. However, if fall water 
levels inundate moist-soil plants too deeply, their seeds 
become "out of reach" to dabbling ducks. 

The effect of increases in summer and fall water levels 
upon the duration of time spent in the Illinois Valley by 
four important species of waterfowl was assessed by a mul- 
tiple regression analysis (Table 7-6 ). Rises in summer 
water levels were more adverse than increases in the fall 
for mallards and green-winged teal, but a rise during the 
fall had the greatest adverse influence on pintails and wigeon, 
High summer water levels were apparently favorable for wigeon. 

A further analysis of the relationship between fall 
water levels and the abundance of five species of dabbling 
ducks is shown in Table 7-7 . The coefficient of determination 
(r2) indicates that 16° of the yearly variation in mallard 



7-12 



Table 7-6 . Multiple Regression Coefficients of Index of 

Duration of Stay of Waterfowl Species (Y) in Relatiori 
to Sum.r.er and Fall Water Levels (X), Peoria and La i 
Grange Pools, 1949-1976. ' 1 

a h r 7d ' 

Species a^^ a^^ a^"" R^ j 

I 

I 

Mallard 28.2 -0.52 -0.11 0.07 | 

Pintail 33.5 -0.12 -1.24 0.19 ! 

G.W. teal 38.2 -1.13 -0.45 0.24 

Wigeon 12.8 2.26 -1.38 0.11 



Point of intercept. 
Slope of summer water level. 
Slope of fall water level. 
Coefficient of determination. 



7-14 
Waterfowl Populations 



and green-winged teal numbers and between 6-81 in other species 
resulted from water level changes. Numbers declined for 
each species as fall water levels rose. 



EFFECTS OF PROPOSED DIVERSION ON WATERFOWL POPULATIONS 



To varying degrees, abundance of dabbling species is 
determined by the availability of moist-soil plant foods. 
The abundance of moist-soil plants is regulated by low water 
in midsummer, and their seed availability to ducks is 
governed by water levels that are slightly above normal 
during the fall. Therefore, any increase in water levels 
during the critical development and growth period (10 July- 
1 October) of moist-soil plants would be detrimental to the 
abundance of the most important species of waterfowl. 

The effect of projected diversion increases on the 
exposure of mud flats and the subsequent development of 
moist-soil food plants is discussed in detail elsewhere 
(see Moist-Soil Plants, page 5-66) . It is pertinent 
to reiterate that increased diversion for all practical 
purposes would eliminate moist-soil food plant resources in 
all but those areas where levees are sufficiently high to 
prevent flooding. 

The loss of moist-soil plant resources would be particu- 
larly detrimental to dabbling duck populations during the 
fall. Pintails, green-winged teal, and blue-winged teal 
numbers would decline drastically. The abundance of mallards, 
the most important duck in the Illinois Valley, would decline, 
but currently not to the extent of other dabblers. 

Mallards obtain up to half of their food requirements 
from waste grain gleaned in harvested corn and soybean 
fields. The remainder of their diets is derived largely 
from moist-soil plant resources. However, there has been a 
steady decline in the amount of waste corn available to 
mallards as continued improvements in harvesting machinery 
reduce field losses of grain. Fall plowing has also greatly 
increased, a practice that turns under most of the waste 
grain. The continued improvement in harvesting equipment 
will probably reduce field losses in the years ahead to the 
extent that mal lards will no longer be able to depend upon 
waste grain for an important part of their food requirements. 
When that situation occurs, numbers will decline dramatically 
unless there are moist-soil plant foods to compensate for the 
loss of corn and soybeans in their diet. 



7-13 



Table 7-7. The Average Height of Fall Water Levels Each 

Year (X) in Relation to Fall Abundance of Dabbling 
Duck? (Y) in La Grange Pool, 1949-1976. 



Species 



Slope 



Y - Intercept 



Mallard 



0.16 0.40 -890,096 18,960,000 



Pintail 



0.06 0.24 



49,143 



960,550 



G.W. teal 



0.16 0.40 



-47,412 



619,770 



B.W. teal 



0.08 0.29 



6,284 



96,290 



Wigeon 



0.07 0.26 



-21,790 



457,200 



The higher the average fall level, the lower the fall abun- 
dance of dabbling ducks. 

r significant at 0.37, p <.05; and 0.25, P <.10. 



7-15 
Waterfowl Populations 



Diving duck numbers should not be adversely affected 
by an increase in summer and fall water levels from 
diversion. They feed primarily on animal life that 
might not change greatly in abundance with an increase in 
water levels. Canada geese and snow geese feed almost 
entirely in fields, thus utilizing little of the native 
food plant resources. Therefore, their abundance would 
not be influenced by any change in water levels. 



WINTER AND SPRING WATER LEVELS 



The spring migration of waterfowl occurs from late 
February through April. Normally during this period 
river and lake levels are high, but even so diverted water 
from Lake Michigan would raise levels still further. At 
Henry (Peoria Pool), the 6,600-cfs diversion would 
have increased spring river levels by 0.22 m (0.7 ft), 
0.06 m (0.2 ft), and 0.40 m (1.3 ft), respectively, in 
1971, 1973, and 1977. A 10,000-cfs diversion would 
have raised the water level 0.22 m (0.7 ft) in 1971 and 
0.86 m (2.8 ft) in 1977. No 10,000-cfs diversion would 
have occurred in 1973. 

Increased diverted water would have raised spring 
levels at Havana (La Grange Pool) as follows: 6,600 cfs -- 
0.12 m (0.4 ft) in 1971, 0.03 m (0.1 ft) in 1973, 0.30 m 
(1.0 ft) in 1977; 10,000 cfs -- 0.15 m (0.5 ft) in 1971, 
no increased diversion in 1973, 0.71 m (2.3 ft) in 1977. 

In the spring of 1971 and 1973, the natural rise of 
the river without diversion inundated bottomland forest 
at Henry and Havana. Any additional water diverted from 
Lake Michigan during those springs would have had minimal 
effect upon waterfowl habitat. Because the natural water 
level was below the tree line in 1977, additional water 
diverted from Lake Michigan would have had a greater effect 
on waterfowl, and possibly a beneficial one if it resulted 
in the flooding of moist-soil food plant beds below the 
elevation of the tree line. 

In conclusion, the proposed increased diversions 
during the spring would probably not have been detrimental 
to waterfowl. A rise in the water would have probably 
made other food resources available to waterfowl. 



CHAPTER 8 : WATERFOWL HARVEST 



The Illinois River valley was -- until the use of 
bait and live decoys were made illegal in 1935 -- one of 
the most famous areas for waterfowl hunting in the nation. 
Since then it has lost some of its luster as hunting suc- 
cess has declined. Some of the decline can be attribu- 
ted to a reduction in continental duck populations with 
the consequent restrictions on kill. But also the decline 
in kill has occurred because of deteriorating food re- 
sources (Bellrose et al., 1979, in press). 

Nevertheless, according to the ten-year average (1966- 
1975) of the kill of ducks by counties in Illinois, a 
yearly average of approximately 37°6 (112,074) of the 301,000 
ducks harvested in the state was bagged in counties as- 
sociated with the Illinois River (Table 8-1 ). This 
ten-year average of the duck harvest by counties in 
Illinois was computed by the U.S. Fish and Wildlife 
Service from hunter questionnaires (Carney et al., 1978). 
Species composition was determined from samples of 
wings submitted by hunters. 

Two other sources of records of the harvest of ducks 
in the Illinois River valley were available. The private 
duck clubs are required by the Illinois Department of 
Conservation to report their waterfowl kill, and biologists 
at state public shooting grounds record the bag of 
hunters using these areas. A tabulation of duck kill 
from these two state sources (Table 8-2 ) indicates an 
average yearly bag of about 47,400 for the three-year 
period, 1975-77. The total kill at duck clubs was almost 
twice as high as at public shooting grounds, but the kill 
per hectare of bottomland was only slightly lower at 
public shooting grounds (Table 8-2). 

We do not know all the causes of the discrepancy 
between federal and state kill data; that is, the U.S. 
Fish and Wildlife Service data by counties (Table 8-1) 
and that obtained by the Department of Conservation from 
private duck clubs and public shooting grounds (Table 8-2) 
in the Illinois Valley. The county data does include 
the kill of ducks made outside the Illinois Valley in 
grain fields, tributary streams, farm ponds, reservoirs. 



8-2 



Table 8-1 . Average Annual Duck Harvest in relation to the 
Water Area of Bottomland Lakes by Counties and 
Navigation Pools in the Illinois River Valley, 
1966-1975. a 











Duck 


Harvest 








Annual 








Hectares 




Duck 


per Ha per Acre 


Area 


of Water 


Upper 


Harvest 
Pools 


Water 


Water 


Grundy 


262.6 




2,418 


9.21 


3.73 


La Salle 


933.4 




6,363 


6.82 


2.76 


Total 


1 ,196.0 




8,781 


7.34 


2.97 






Peoria Pool 






La Salle 


215.6 




1,470 


6.82 


2.76 


Bureau 


776.3 




7,036 


9.06 


3.67 


Putnam 


2,817.1 




10,336 


3.67 


1 .49 


Marshall 


2,900.5 




13,812 


4.76 


1 .93 


Woodford 


3,564.6 




7,818 


2.19 


0.89 


Peoria 


2,469.1 




3,694 


1 .50 


0.61 


Tazewell 


552.7 




1,323 


2.39 


0.97 



Total 



Peoria 

Tazewell 

Fulton 

Mason 

Schuyler 

Cass 

Brown 

Total 



Cass 

Morgan 

Pike 

Scott 

Greene 

Calhoun 

Jersey 

Total 



13,295.9 



45,489 



La Grange Pool 

331.6 496 

819.7 1,962 
2,215.8 6,598 
5,825.0 12,005 

356.7 2,362 

1,103.6 8,582 

266.2 474 



10, 


,918.6 




32,479 






Alton 


Pool 




200.2 




1 ,557 




507.3 




4,787 




105.4 




1,657 




99.2 




50 




0.0 




3,706 


1 


,714.1 




3,889 




563.3 




9,679 


3 


,189.5 




25,325 



112,074 



3.42 



50 
39 
98 
06 
62 
78 
78 



Total All Pools 28,600.0 

(70,670.6 acres) 
^Data summarized from Carney et al., T9T! 



2.97 



7.78 

9.44 

15.72 

0.50 

2.27 
17.18 

7.94 

3.92 



1 .3! 



0.61 
0.97 
1.21 
0.83 
2.68 
3.15 
0.72 

1 .20 



3. 15 
3.82 
6.36 
0.20 

0.92 
6.95 

3. 21 

1 .59 



Table 8-2 . The Number, Size, Hunting Activity, and Duck 

Harvest of Private Waterfowl Hunting Clubs and 
State Public Shooting Grounds by Navigation Pools 
in the Illinois River Valley. Private duck club 
data were averaged for 1976-77; public waterfowl 
hunting area data Avcre averaged for 1975-77.^''^ 



Navi - 

gation 

Pool 


Areas 
Reportir 


g Ha^ 


Hunter 
Davs 


Re- 
corded 
Kill 


Kill/ 
Ha c 


Kill/ 
Hunter 
Day 


Hunter 
Days/ 
Ha c 










Duck Clu 


bs 








Upper 


11 


2, 


331 .4 


986 


1,555 


0.67 


1 .58 


0.42 


Peoria 


126 


9, 


662.7 


7,589 


17,792 


1 .84 


2.34 


0.79 


La Gran 


ge 83 


11 


185.8 


4,237 


10,834 


0.97 


2.56 


0.38 


Alton 


11 


1 


013.0 


563 


884 


0.87 


1 .57 


0.56 


Total 


231 


24 


192.9 


13,375 


31,065 


1 .28 


2.32 


0.55 








Public Huntin 


g Areas 








Upper 







- 


- 


- 


- 


- 


- 


Peoria 


3 


4 


214.2 


4,906 


3,572 


0.85 


0.73 


1 .16 


La Gran 


ge 4 


6 


220.4 


6,090 


4,693 


0.75 


0.77 


0.98 


Alton 


4 


3 


775.0 


11 ,131 


8,057 


2.13 


0.72 


2.95 



Total 11 14,209.6 22,127 16,322 1.15 0.74 1.56 

Combined Areas 

Upper 2,331.4 1,555 0.67 0.42 

Peoria 13,876.9 21,364 1.54 0.90 

La Grange 17,406.2 15,527 0.89 0.59 

Alton 4,788.0 8,941 1.87 2.44 

Total 38,402.5 47,387 1.23 0.93 

^Data provided by the Illinois Department of Conservation. 

Approximately one-third of the private duck club land is 
non-wetlands such as woods or areas in cultivation. State 
public shooting areas consist of about 521> non-wetland habi- 
tat. Public shooting data are summarized from only those 
areas for which kill data wcreprovided. No harvest data were 
available for an additional 1,363.5 ha of state public water- 
fowl areas . 

Total size of private and/or public area. 



8-4 

Harvest 



and the like. However, this kill is not believed to be of 
the magnitude that would account for the spread between 
federal and state figures. 

It should be noted, however, that the duck club kill 
record is minimal. Some clubs do not report their kill and 
an oversight by members in neglecting to record their 
daily kill occurs to varying degrees at most clubs. 
Thus, the actual annual kill of ducks in the Illinois 
Valley is probably between a minimum of 50,000 (Table 8-2) 
and a maximum of 100,000 (Table 8-1). 

The kill of ducks outside of the valley but within 
counties adjacent to it would accrue from the concentrations 
of waterfowl within the valley. Appreciable numbers of 
ducks fan out from refuge areas within the valley to 
search for food elsewhere. Such flight activity enables 
hunters outside of private duck clubs and state public 
shooting grounds to participate in bagging waterfowl. 

It should be noted that the county duck kill per hec- 
tare (Table 8-1 ) was based on the area of bottomland 
lakes within a county whereas the kill and hunter activity 
per hectare at private duck clubs and public shooting 
grounds (Table 8-2 ) was based on the total land -- 
both upland and wetlands -- in their possession. We 
believe that from 50 to 701 of the lands owned by private 
duck clubs and in state public shooting grounds are 
wetlands used by waterfowl, the remainder is wooded or 
cultivated . 

The greatest duck kill per hectare of water occurred 
in the Upper Pools, followed by the Alton Pool, Peoria 
Pool and La Grange Pool (Table 8-1 ). The duck kill per 
hectare of total area was highest in the Alton Pool be- 
cause of the large kill at public shooting grounds (Table 8-2) 
Both private clubs and public shooting grounds in the Peoria 
Pool had a higher duck kill per hectare of total area 
than those in the La Grange Pool (Table 8-2). 

The composition of the duck kill by species from two 
sources (U.S. Fish and Wildlife Service harvest data 
QZarney et al., 1978], and Illinois Department of Conserva- 
tion private duck club records) is shown in Table 8-3. 
According to the federal data, the ki 11 of ma llards and 
black ducks formed 60.81 of the bag. The kill of the 
same species formed 73.9b of the bag at private duck clubs. 
Of the two species, mallards and black ducks, the former 
is at least 20 times more abundant than the latter, but 
they are combined here because of their close relationship 
and habits. 



Table 8-3 . Average Annual Harvest of Each Duck Species in 

the Illinois River Valley According to U.S. Fish 
5 Wildlife Service Data compiled by Counties, 
1966-1975^, and Illinois Department of Conser- 
vation Records for Private Duck Clubs, 1976-1977 





County 






Duck Club 




Spe cies 


# Bagged 


c 




# Bagged 








Dabbl 


ing Ducks 












Wood duck 


15,191 


10 


04 


1 ,700 


5 


94 


American wigeon 


6,790 


4 


49 


1 ,021 


5 


57 


Gadwall 


3,745 


2 


47 


554 


1 


94 


Green-winged teal 


9,859 


6 


51 


1,790 


6 


25 


Mallard 


87,925 


58 


10 


20,769 


72 


56 


Black duck 


4,156 


2 


75 


382 


1 


53 


Pintail 


4,291 


2 


84 


653 


2 


28 


Blue-winged teal 


7,784 


5 


14 


635 


2 


22 


Shoveler 


1,333 





88 


120 





42 


Divin 


g Ducks 












Canvasback 


741 





49 


74 





26 


Redhead 


1 ,130 





75 


74 





26 


Ring-necked duck 


2,272 


1 


50 


221 





77 


Greater s caup 


302 





20 


- 






Lesser s caup 


3,693 


2 


44 


531 


1 


86 


Oldsquaw 


45 





03 


- 






Black s coter 


62 





04 


- 






White-winged scoter 


49 





03 


- 






Bufflehead 


543 





36 


53 





19 


Common g Dldeneye 


518 





34 


- 






Hooded merganser 


406 





27 


- 






Red-breasted merganser 


153 





10 


- 






Common merganser 


112 





07 


- 






Ruddy d uck 


241 





16 


42 





15 


Total 


151,341 


100 


00 


28,619 


100 


00 



Includes kill along the Mississippi River for Pike and 
Calhoun counties. Kill data in Table 8-1 does not include 
that from the Mississippi River. Data summarized from 
Carney et al. (1978) . 



Harvest 



Some of the difference in s 
harvest between the two sets of 
private duck club hunters are fr 
for mallards than non-club hunte 
more correctly identified in the 
Service kill data because traine 
samples of wings submitted by hu 
(Table 8-3 ) show wood ducks fo 
second to mallards; green-winged 
bag, composing 6.51.; blue-winged 
American wigeon fifth, A.S%; and 



pecies composition of the 
data may occur because 
equently more selective 
rs . Other species are 

U.S. Fish and Wildlife 
d biologists identify 
nters. These data 
rmed ^0% of the bag, 

teal were third in the 

teal fourth, 5.11,; 

pintails sixth, 2.8°6. 



data, 

in th 

ducks 

depen 

basic 

ma 11a 

food 

1959) 

stead 

and i 

this 

ducks 

resou 



It i 
res 

e II 
(Ta 

d up 

f 00 

rds 
from 
. H 
ily 
t is 
supp 
wi 1 
rces 



s apparent 
pectively , 
linois Rive 
ble 8-3 ) . 
on the seed 
d supply (A 
and black d 

waste grai 
owever, fal 
reduced the 

anticipate 
ly will cea 
1 need to d 



from t 
that 9 
r vail 

For 
s of m 
nderso 
ucks o 
n in h 
1 plow 
avai 1 
d that 
se. A 
epend 



he Feder 
5.2% and 
ey is ma 
the most 
oist- soi 
n, 1959) 
btained 
arvested 
ing and 
ability 
within 
t that t 
entirely 



al and S 

96.51 o 
de up of 

part th 

1 plants 

At on 

almost h 

cornf ie 
improved 
of this 
another 
ime mall 

upon na 



tate harvest 
f the duck kill 

dabbling 
ese ducks 

for their 
e time 

alf of their 
Ids (Anderson, 

combines have 
food source, 
two decades 
ards and black 
tural food 



Several factors affect the yearly k 
(1) size of local populations, (2) food 
(3) water levels, and (4) weather condit 
populations are determined by the magnit 
fall flight from northern breeding groun 
local food resources that are available, 
possible, hunters place blinds in or nea 
will attract ducks. The better the food 
blinds, the better the hunting success, 
food resources are lacking, it is much m 
to decoy passing flocks. Where water le 
low, hunters have difficulty finding sui 
blinds and may have difficulty reaching 
other hand, water levels created by dive 
advantageous to blind sites, but because 
levels food resources would be unavailab 
ducks. Cold, but not freezing weather, 
the kill of ducks. Freezing weather is 
hunting because the shallow lakes in the 
quickly freeze over, greatly diminishing 
available for hunting. Cool weather inc 



ill of ducks: 
avai labi li ty , 
ions. Local 
ude of the 
ds plus the 

As much as 
r food beds that 

resource near 

When and where 
ore difficult 
vels are too 
table sites for 
them. On the 
rsion would be 

of higher water 
le to dabbling 
and wind enhance 
detrimental to 

Illinois Valley 

the areas 
reases the ducks' 



;-7 



Harvest 



demand for food, and windy weather dislodges birds from 
resting on open bodies of water. An increase in flight 
activity results in an increase in bag opportunity. 
Weather conditions are quite variable from year to year, 
but over a period of years they would not be a factor in 
the analyses of diverted water. 



EFFECTS OF DIVERSION 



The diversion of 6,600 cfs or 10,000 cfs of Lake 
Michigan water into the Illinois River would have a dele- 
terious effect upon the kill of waterfowl. The effect 
would oc ur through a reduction in the natural food 
resource: as discussed in the section on moist-soil plants 
(Chapter 5 ). The 6,600-cfs diversion would eliminate 
the appearance of mud flats in the Peoria Pool, thereby 
eliminating the production of moist-soil plant foods. 
The adverse effect of the 6 ,600 -cfs diversion would not be 
quite as great in the La Grange or Alton pools because 
these lake beds are higher in relation to the river level. 
Nevertheless, only in an occasional year would 6,600 cfs 
expose limited mud flats in these pools; at the 10,000-cfs 
diversion rate, the area of mud flats would be further 
restricted . 

We believe that the elimination of moist-soil food 
resources for waterfowl in the Illinois V^alley would 
reduce the duck kill by 40 to SOs. We based this assump- 
tion on evidence from a prior food disappearance in the 
Illinois Valley. During the period 1938-1942, diving 
ducks composed 9.21. of the bag at Illinois Valley duck 
clubs (Bellrose, 1944a). However, in 1976-1977, the 
composition of the diving duck bag at private duck clubs 
(Table 8-3 ) amounted to only 3.5°o. A reduction of 
2.6 times in the diving duck component of the kill be- 
tween these two periods is attributed to the decline in 
diving duck populations following an important loss in 
their food supply of animal matter in the river that has 
persisted since the mid-1950's (Mills et al., 1966). 

The comparative loss in diving duck populations 
resulting from the decline in food supplies was much 
greater than that in the kill (Mills et al., 1966: 18-20). 
The reason that the kill did not plummet as drastically 
as population levels is that flight ducks passing through 
the valley in migration provide a minimum degree of 
hunting opportunity. Even without food resources, the 



Harves t 



backwater lakes in the Illinois Valley would attract tired 
and thirsty migrating ducks to a brief residence. However, 
hunting success depends primarily on the large proportion 
of fall migrants that remain an average of three weeks 
(Bellrose et al., 1979, in press). 

In relation to the potential loss of a major food 
resource, the decline in the harvest of dabbling ducks 
in the valley, with the exception of the mallard, would 
probably be greater than the decline that occurred in 
the diving duck kill. Our reasoning is that diving 
ducks migrate farther between rest stops than do dabbling 
ducks (Bellrose, 1976). Because of this, they need to 
use water areas in the Illinois Valley for resting purposes 
more than do dabblers. Dabbling ducks are able to 
utilize a greater variety of water areas for resting than 
divers and, therefore, have more options to find suitable 
areas in migration. Hence, food supplies weigh more 
heavily on where dabbling ducks stop than on divers. 
Thus, with a reduction in food supplies, dabbling ducks 
would be more prone to bypass the Illinois Valley. 

Currently, the mallard kill would not decline as 
greatly as other dabblers because part of its food supply 
is obtained from waste grain in harvested fields. However, 
with each passing year, this source of food is becoming 
less available and we believe that within two decades 
only insignificant amounts will remain. Thus, ultimately 
the mallard kill would be reduced comparably to that of 
other dabbling ducks. 

Private and state waterfowl hunting lands (total 
wetland and non-wetland area) in the Illinois River 
valley that reported their waterfowl harvest embrace a 
minimum of 38,403 hectares (94,855 acres) (Table 8-2). 
Minimum is used advisedly because we know of at least two 
clubs that own sizeable areas that are not licensed by 
the Illinois Department of Conservation. In addition, there 
are 2,712 hectares (6,701 acres) in private clubs and 1,363.5 
ha (3,368 acres) in state areas that did not report their 
kill. Besides hunting areas, the U.S. Fish and Wildlife 
Service has three refuges totaling 4,855 hectares (11,995 
acres) that provide resting and feeding areas for 
waterfowl. Thus, vested interests in waterfowl own at least 
47,333 ha (116,960 acres) within the floodplain of the 
Illinois River. There are approximately 85,020 ha (210,000 
acres) in the unleveed portion of the 161,943-ha (400,000- 
acre) floodplain (Mulvihill and Cornish, 1929). Increased 
diversion would have a devastating effect upon this ex- 
tensive area of the Illinois River valley devoted to 
waterfowl hunting and management. 



9- 1 



CHAPTER 9 : SHOREBIRDS, GULLS, AND TERNS 



The order Charadriif ormes encompasses a diverse collection 
of shore- inhabiting birds commonly referred to as shorebirds. 
Members of the gull, tern, plover, sandpiper, turnstone, 
avocet, and phalarope families of this order occur in the 
Illinois Valley. However, only 2 species of this highly 
migratory group are known to nest in the project area. The 
majority are seasonal transients that occupy the valley for 
a few weeks or months each year while en route to breeding 
or wintering grounds. 

Because gulls and terns are physically and ecologically 
different from the remainder of the shorebirds, they will be 
discussed separately. 

WADING SHOREBIRDS 



The wading shorebirds average greater distances in 
migration than any other group of birds. The breeding 
grounds of many species extend as far north as the Arctic 
tundra and the wintering grounds are located as far south 
as Chile and Argentina (Stout et al., 1967). White-rumped 
sandpipers ( Erolia fuscicollis ) make a 14,500-km (9,000-mile) 
migration flight twice each year and serve as an example of 
the marvelous flight capabilities of shorebirds (Stout et al. 
1967: 49). Fall migration to the wintering grounds in the 
south includes stopovers in the prairies of Canada and the 
Dakotas and in areas of the Illinois River valley. American 
golden plovers ( Pluvial i s dominica ) , which hav^e been known 
to fly as far as 3,200 km (2,000 miles) between stops (Stout 
et al., 1967: 49), provide another example of the stamina of 
shorebirds. Such long, strenuous migration flights result 
in tremendous energy expenditures, especially for the young 
that are not physically mature. Some of the pectoral sand- 
pipers ( Erolia melanotos ) arriving on the pampas of South 
America after their 11,000-km (7,000-mile) southward journey 
still have yellow natal down on their heads (Stout et al . , 
1967: 109). Mud flats exposed along the Illinois River and 



9-2 

Shorebirds 



its backwaters by the receding waters of summer, and the 
shallow pools of backwater marshes provide some of the es- 
sential feeding and resting areas for the fall migration. 
The return migration in the spring is much faster than the 
fall flight because of the pressures of the breeding cycle 
(Stout et al. , 1967: 52) . 

Wading shorebirds are equipped with sensitive bills 
for probing in the mud and shallow water in search of aquatic 
insects, insect larvae, snails, mollusks, and crustaceans. 
The various species of shorebirds have a variety of leg 
lengths that allow for occupation and utilization of different 
zones of mud flats, representing slightly different niches. 
The bare shores also serve as resting and roosting places 
for the migrants which stand or crouch on the sand or mud. 

Two species of wading shorebirds are thought to nest in 
the project area. Common snipes ( Capel la gallinago ) , if 
present as breeders, occur in wet areas and along open creeks 
of the valley (Bohlen, 1978:52). Swampy thickets and edge 
situations near woods attract the nesting American woodcock 
( Philohela minor ) (Bent, 1927: 65). The woodcock is more 
of an upland species and only occasionally encounters these 
nesting habitat conditions within the confines of the project 
area. Spotted sandpipers ( Acti tix macularia ) and killdeers 
( Charadrius voci ferus j are common breeding species through- 
out Illinois but, because of their preference for field and 
pasture nest sites (Stout et al., 1967: 211; Bent, 1929: 205), 
they largely nest outside of the project area. 

GULLS AND TERNS 



Gulls and terns are powerful fliers but migration flights 
made by most of the species do not compare with the ex- 
tended journeys of many wading shorebirds. Breeding grounds 
are located along the coasts and larger lakes of Canada as 
well as along the Great Lakes. The seacoasts of the U.S., 
the major river systems emptying into the Gulf of Mexico, and, 
less frequently, the coasts of northern South America are 
wintering areas. Many gulls and terns observed in the 
Illinois Valley are migrating between the Great Lakes and 
the Gulf of Mexico, but large numbers of ring-billed ( Larus 
delawarensis ) and herring gulls (L. argentatus ) winter in the 
project area. 

Gulls and terns, with their short legs, webbed feet, 
and stout bills, are adapted for a more aquatic lifestyle than 
wading shorebirds. Gulls are primarily scavengers that land 



9-3 
Shorebirds 



on the water or shore to feed, whereas terns dive headfirst 
into water to capture small fish and insects (Robbins et al. 
1966: 132, 142). hJud flats are used by the birds for con- 
venient resting and roosting places but are not essential 
because gulls and terns are able to rest on the water or on 
structures projecting from the water. 

No gulls or terns are known to currently nest in the 
Illinois Valley. In the past, black terns ( Chlidonias 
niger ) nested in the marsh areas of Putnam and Cook counties 
CBent, 1921: 298), but this species supposedly no longer 
nests there because the prerequisite marsh habitat has 
disappeared. Black terns were included in the Illinois 
Endangered Species Act of 1973 because their Illinois 
breeding population was in danger of extirpation. 



1978 FIELD INVENTORY 

Shorebird populations, reduced to pitiful remnants 
in the mid-1800's by market hunters, have been increasing 
since 1918 when the Migratory Bird Treaty Act curtailed 
the rampant killing. During the 1978 field inventory, 
ground and aerial censuses were conducted to investigate 
the present status of shorebirds in the Illinois Valley. 
Aerial censuses of lakes in the La Grange Pool (Figure 9-1 ) 
flown by Bellrose revealed the gross numbers of shorebirds 
using the areas (Table 9-1). Intensive ground counts made 
from the cross levee of Lake Chautauqua (Figure 9-1) by 
Robert Crompton, Illinois Natural History Survey, provided 
a refined sample of the shorebirds utilizing the mud 
flats (Table 9-2). Ground surveys of Weis, Chau- 
tauqua, and Meredosia lakes provided by Tom Sanford, U.S. 
Fish and Wildlife Service, supplied information on seasonal 
abundance and species diversity of shorebirds in 3 regions 
of the river valley (Peoria, La Grange, and Alton pools) 
(Figure 3-1, Tables 9-5, 9-4, 9-5, 9-6, 9-7). 
Gulls and terns will be discussed separately from the wading 
shorebirds . 



Wading Shorebirds 

The fall migration of wading shorebirds through the 
lower Illinois Valley (La Grange Pool) in 1978 was well under- 
way by 21 August (Table 9-1). Censuses may need to begin 
earlier in subsequent years to establish the arrival time 
of the first waves of migrants. Numbers of shorebirds in 
the La Grange Pool peaked at over 12,500 birds during the 



9-4 




1 - CAMERON NATIONAL UILDIIFE REFUGE 
Z - CHAUTAUQUA NATIONAL WILDLIFE BEFUGE 

3 - MEBED051A NATIONAL WILDLIFE REFUGE 

4 - LA GRANGE POOL 



Figure 9-1. Localities within the project area censused 
for shorcbirds. 



9-5 



Table 9-1. Aerial Censuses of Total Shorebird Numbers in the 
Lower Illinois Valley (La Grange Pool), August- 
September 1978. 





21 


28 


5 


13 


Average 




Aug. 


Aug. 


Sept. 


Sept. 


per 


Area 


1978 


1978 


1978 


1978 


'flight 


Spring Lake 


350 


360 


140 


20 


218 


Rice Lake 


35 








35 


Beebe Lake 














Goose Lake 


25 


no 







45 


Clear Lake 


400 


1,250 


350 


505 


626 


Chautauqua Lake 


4,900 


6,650 


10,460 


2,180 


6,048 


Quiver Lake 


30 





5 


15 


13 


^1atanzas Lake 






125 


5 


65 


Bath Lake 


125 


40 


30 


5 


50 


Moscow Lake 


60 


10 


35 


40 


36 


Grass Lake 






15 




15 


Jack Lake 


100 


75 


105 





70 


Patterson Bay 


425 







10 


145 


Snicarte Island 


75 


115 


10 


30 


58 


Ingram Lake 


270 


155 


210 


175 


205 


Stewart Lake 


260 


1 ,150 


240 


160 


453 


Chain Lake 


150 


210 


10 


40 


103 


Crane Lake 
















Cuba Island 


175 










58 


Sangamon River bottoms 






15 


15 


Sanganois 












Conservat ion 


Area 












Sangamon Bay 





125 


95 




73 


Sangamon Lake 









40 


20 


Treadway Lake 





250 




150 


133 


Muscooten Bay 


60 


465 


765 


390 


420 


Total 


7,440 


10,965 


12,595 


3,780 


8,902 



9-6 



Table9-2. 


N 


uml 


)ers 


of : 


Sh 


oreb 


irds 


, Gull 


s , an 


d Terns from Ground 




C 


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of 


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Chautauqua 


, Aug 


ust-: 


September , 


1978.^ 




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1 


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37 


45 






9/15 


















2 


4 


19 


24 






9/20 














9 


2 


13 


16 


21 


24 






Total 






























Number 














87 


5 


104 


168 


191 


299 


































Percent 






























of Total 
(Species 














4.2 


0.2 


5.0 


8.0 


9.1 


14.3 


































Composi tion) 





























Sheet 1 of 3 



9-7 



Table 9-2continued -- Lake Chautauqua Shorebird Ground Census 



Date 






-Q 


•t-H 


1 


c 


U^ 


-a 


I— 


c 


Z5 


re 


pa 


t/5 



O D. 



(Li CO 



rt CO 

CQ IT, 



■t-i Oh 

ro c 

J in 



T3 
0) 



re -H 
p. & 

E C 

<D re 



C &- O 

t- -r-l <-> 

(A; C -^ (- 

S lA; a: +-> 



8/17 

8/24 

8/25 

8/28^^ 

8/29 

8/30 

8/31 

9/1 

9/6 

9/7 

9/8 

9/n 

9/13 

9/13^^ 

9/14 

9/15 

9/20 



30 
24 
32 

400 
40 
26 
29 
34 
45 
45 
61 
29 
46 

500 
69 
40 
44 



12 
12 
16 

7 



30 



20 
17 
22 
200 
22 
20 
20 
26 
31 
26 
37 
26 
23 
50 
40 
28 
34 



20 



Total 

Number 

Percent of 
Total 
(Spec ies 
Compos i t ion) 



0.2 



594 7 80 392 7 



28.3 0.5 3.8 18.7 0.3 



Slieet 2 of 3 



9-8 



Table 9-2concluded -- Lake Chautauqua Shorebird Ground Census 



Date 





(U 


ir, 


c 


- 


o 


C 


!-, 


o 


TO 


Vt 


1 — ( 


1— ( 


TO 


.rH 


XI 


S 


C 



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.PH 


C i/i 


1— 1 

AS 


X3 


S- CD 

O -rH 


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C U 


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C --H 


^ OJ 


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C Cu 


u. oo 


Di M 


HD CO 



Total 



8/17 

8/24 

8/25 

8/28^ 

8/29 

8/30 

8/31 

9/1 

9/6 

9/7 

9/8 

9/1 1 

9/13 

9/13^ 

9/14 

9/15 

9/20 



1000 



10 
9 

9 

5 
10 
12 
14 
13 
13 

5 
12 

16 

7 

22 



115 
114 
109 

93 
71 
94 
128 
159 
180 
190 
100 
184 

242 
124 
193 



Total 
Number 

Percent of 
Total 
(Species 
Compos i t ion) 



157 



7.5 



2096 



99.9 



Counts by Robert D. Crompton, Illinois Natural History Survey. 

Estimate made for the entire lake by Bellrose. Not included in 
totals or percentages. 

Estimate made for the entire lake by Richard Sandburg, Decatur, 
Illinois. Not included in totals or percentages. 



Sheet 3 of 3 



9-9 



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9-15 



Table 9-6. Number of Wading Shorebird Use-Days^ at Mark 
Twain NWR, 19 73-1978.^ 











Period 










Year 


Jan 


. -March 


Apr . -June 


Jul . -Sept 




Oct . -Dec. 


Total 






Cameron 


Division (Peoria 


Pool) 




1973 




- 




- 


67,160 




1 ,340 


68,500 


1974 









30 


17,940 




2,050 


20,020 


1975 









30 


22,130 




7,860 


30,020 


1976 












20,725 




3,882 


24,607 


1977 


1 


,500 




700 


22,490 




1 ,995 


26,685 


1978 




530 


1 


,810 


75,050 




3,880 


81 ,270 


Ave . 




406 




514 


37,583 




3,501 


41,850 






Chautau 


qua 


Division (La Gran 


ge 


Pool) 





1973 

1974 

1975 300 

1976 510 

1977 3,200 

1978 1,630 

Ave. 1,128 2,350 358,217 12,606 373,722 
Meredosia Division (Alton Pool) 



- 


1,350 


700 


259 


168 


840 


270 


171 


205 


135 


72 


329 


1,900 


63 


730 


9,185 


322 


500 



30 


550 


1 ,381 


,250 


15 


622 


184 


721 


9 


915 


181 


690 


4 


105 


77 


079 


6 


195 


75 


025 


9 


250 


342 


565 



1973 


_ 


. 


88,480 


880 


89,360 


1974 








17,940 


765 


18,705 


1975 








103,610 


5,205 


108,815 


1976 


100 





94,450 


2,975 


97,525 


1977 


1 ,050 


400 


28,205 


2,020 


31,675 


1978 


740 


2,540 


100,900 


4,750 


108,930 


Ave . 


378 


588 


72,264 


2,766 


75,855 



^One shorebird spending one day in the Illinois Valley = ( 
use-day . 

Censuses supplied by Tom Sanford, U.S. Fish and Wildlife 
Service, Chautauqua Refuge, Havana, Illinois. 



9-16 



Table 9- 



Number of Gull and Tern Use-Days' 
NWR, 1973-1978.° 



at Mark Twain 







Period 








Year 


Jan . -March 


Apr. -June J 


ul . -Sept 


Oct . -Dec. 


Total 




Cameron Division 


(Peoria 


Pool) 




197 5 


- 


- 





6,200 


6,200 


1974 


8,100 


550 


3,500 


6,750 


18,500 


1975 


8,950 


450 


1 ,150 


7,750 


18,500 


1976 


3,600 


1 ,900 


1,225 


7,225 


15,950 


1977 


9,800 


1,000 


1,180 


7,550 


19,550 


1978 


7,600 


1,050 


5,500 


10,900 


22,850 


Ave . 


7,610 


950 


1 ,695 


7,696 


16,522 




Chautau 


qua Division 


(La Grange Pool) 




1975 


- 


- 


1 ,940 


45,220 


45,160 


1974 


42,050 


650 


50,450 


66,928 


140,058 


1975 


95,160 


9,500 


7,555 


59,424 


169,419 


1976 


47,000 


2,975 


5,757 


12,690 


66,402 


1977 


51,600 


4,580 


6,990 


20,150 


85,120 


1978 


45,000 


9,700 


11,955 


45,100 


109,755 


Ave . 


55,758 


5,441 


10,598 


40,919 


102,516 




Mered 


osia Division (Alton 


Pool) 




1975 


- 


- 





12,500 


12,500 


1974 


8,100 


550 


5,500 


1 ,125 


12,875 


1975 


8,950 


350 


5,675 


7,750 


20,725 


1976 


5,400 


1,350 


5,125 


6,475 


16,550 


1977 


9,000 


580 


1 ,615 


4,195 


15,590 


1978 


18,000 


4,145 


7,080 


9,950 


59,175 



Ave 



9,890 



1 ,555 



5,155 



6,966 



19,469 



One shorebird spending one day in the Illinois Valley = one 
use- day . 



Censuses supplied by Tom Sanford, U.S. Fish and Wildlife 
Service, Chautauqua Refuge, Havana, Illinois. 



9-17 



Shorebirds 



last week of August and the first week of September, 1978 
(Table 9-1). This peak in migrant numbers coincided with 
the normal period of maximum mud flat exposure in the 
Illinois Valley. Availability of mud flats, weather con- 
ditions, population numbers, and other factors probably 
cause yearly variations in the migration chronology of 
shorebirds. No previous aerial censuses have been made 
to allow comparison. 

The largest concentrations of shorebirds in the La 
Grange Pool during the fall of 1978 were found at Lake 
Chautauqua (Table L'-l ). Clear and Stewart lakes and Mus- 
cooten Bay also harbored large numbers of the migrants. 
Selection of the lakes by the shorebirds was probably 
governed by such factors as the amount of mud flats and 
food availability. 



Intensive 
that pectoral a 
and lesser and 
melanoleucus ) w 
mud flats STIrin 



specie 
comb in 
specie 
birds . 
presum 
By app 
the in 
obtain 
specie 
through 



s compris 
ed) , of t 
s complet 
A few u 
ably repr 
lying the 
tensive g 
ed by aer 
s abundan 
9-11). 



groun 
nd se 
great 
ere t 
g Aug 
ed 28 
he bi 
ed th 
nknow 
esent 
perc 
round 
ial s 
ce pe 



d censu 
mipalma 
er yell 
he most 
ust and 
"o , 1 9 °a , 
rds pre 
e assor 
n indiv 
at ives 
ent spe 
census 
urveys 
r lake 



ses a 

ted s 

owl eg 

comm 

Sept 

14°6, 

sent 
tment 
idual 
of le 
cies 
es (T 
(Tabl 
have 



t Lak 
andpi 
s (Tr 
on sp 
ember 

and 
(Tabl 

of t 
s wer 

SS CO 

compo 
able 
e 9-1 
been 



e Cha 

pers 

inga 



utau 
(Cal 



qua 
idri 



flav 



ipgs 



ecies 
(Tab 
9% , r 
e 9-2 
he mo 
e obs 
mmon 
s i t i o 
0-2 ) 
) , pr 
made 



uti 
le 9- 
espe 
). 

re c 
erve 
or r 
n ob 
to t 
edic 
(Tab 



li zi 

2 ). 

ctiv 

High 

ommo 

d an 

are 

tain 

he t 

tion 

les 



revealed 
£ pus i 1 lus ) 

and T . 
ng the 

These 
ely (70'o 
t other 
n shore- 
d were 
species . 
ed from 
otal counts 
s of 
9-8 



Ground surveys provided by Tom Sanford 
llife Service, supplied comprehens ive inf 
)ers and species of shorebirds utilizing 
.ey between 1973 and 1978 (Tables 9-3 th 
:oral sandpipers, again the most abundan 
Is in the areas, were followed in abunda 
bowlegs, stilt and least sandpipers ( Mic 
]S and Calidris m inut i 11a ) , American gol 
rjeers, and greater yellowlegs (Tables 9 
semipalmated sandpiper, quite common at 
.ng the August and September counts (Tab 
;picuously absent from the abundant shor 
9-4, 9-5. . An explanation for the e 
:ance of this species shown by the inten 
;uses might be that it concentrates spec 
Ltat areas similar to the area surveyed 
ma . 



, U.S. Fish and 
ormation on 

the 1 1 linois 
rough 9-6) . 
t wading shore- 
nce by lesser 
ropalama himan - 
den plovers , 
-3, 9-4, 9-5) . 

Lake Chautauqua 
le 9-2) , is 
ebirds in Tables 
xaggerated im- 
sive ground 
ifically in 
at Lake Chau- 



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9-22 



Shorebirds 



Over a six-year period, 33 total species of wading 
shorebirds were identified at the three areas censused by 
ground observers (Tables 9-3, 9-4, 9-5 ). These extensive 
ground surveys detected such uncommon or rare shorebirds 
(see Table C-9 for status) as American avocets ( Recurvi rostra 
americana), piping plovers ( Charadr i us melodus ) , marbled and 
Hudsonian godwits ( Limosa f edoa and L. haemas t ica ) , willets 
( Catoptrophorus s emipalma tus ) , buff -breas ted sandpipers 
( Tryngitcs subruf icol li s )~ red knots ( Calidris canutus ) , sharp- 
tailed sandpipers (C . a cuminata ) , and northern phalaropes 
( Lobipes lobatus ) . Numbers of individual species varied 
tremendously from year to year, but these fluctuations cannot 
be attributed to any one factor. 

Use of the Illinois Valley by wading shorebirds was 
heaviest within the July-September census period (Table L - 6 ) . 
The majority of the fall migrants passed through the project 
area during these months when water levels were the lowest 
and mud flat exposure was the greatest, thus providing 
ample areas for feeding and resting. Substantial numbers of 
late migrants still occupied the areas between October and 
December, but few, if any, shorebirds overwintered in the 
valley (Table 9-6). Use in the spring was limited pri- 
marily because mud flats are usually inundated until mid- 
summer. Exceptionally heavy spring usage of the census 
areas from January to June, 1977, and January to March, 
1978 (Table 9-6) corresponded wi th periods of unseasonably 
low water levels (Table 9-12) that exposed extensive areas of 
mud flats. No obvious relationships existed between water 
levels (Table 9-12) (and the resulting presence or absence of 
mud flats) and total shorebird usage of the areas censused 
on a year-to-year basis. 

Total shorebird usage of the 3 census areas during the 
6-year survey period ranged from 130,000 use-davs in 1977 to 
over 1.5 million use-days in 1973 (Table 9-6). Lake Chautau- 
ua annually hosted the largest number of shorebirds 
ollowed by Meredosia Lake and then V.'eis Lake (Cameron Di- 
vision, Mark Twain NKR) . If these lakes are characteristic 
of their respective regions of the river, La Grange Pool 
supports the greatest numbers of shorebirds, followed by 
Alton Pool and then Peoria Pool. 

Lake Chautauqua also had the greatest species diversity 
with a total of 33 species sighted over the 6-year survey 
period (Table 9-4). Twenty to 25 species were often sighted 
in one day at this lake. The Weis and Meredosia Lake sur- 
veys were comparable to one another, with 21 and 22 different 
species sighted, respectively (Tables 9-3 and 9-5). Species 



? 



9-23 



Table 9-12. Average Water Levels in Meters (Feet) at Havana, 
1973-1978.^ 



Period 

Year Jan . -March Apri 1- June July-Sept . Oct . -Dec . 

1973 4.72 (15.48) 5.73 (18.79) 2.50 (8.20) 2.56 ( 8.40) 

1974 4.79 (15.71) 5.31 (17.42) 2.62 (8.59) 2.12 ( 6.95) 

1975 3.95 (12.96) 4.40 (14.43) 2.41 (7.90) 2.23 ( 7.31) 

1976 3.68 (12.10) 3.81 (12.50) 1.96 (6.43) 1.73 ( 5.67) 

1977 2.84 ( 9.32) 2.44 ( 8.00) 2.68 (8.79) 3.63 (11.91) 

1978 3.31 (10.86) 4.44 (14.56) 2.73 (8.95) 1.95 ( 6.40) 



^Data compiled from daily river stages. National Weather 
Service, U.S. Department of Commerce, 1973-1978. 



9-24 



Shorebirds 



diversity has generally been on the increase for the past 6 
years at the Weis and Meredosia areas, but diversity reached 
its highest level at Chautauqua in 1976. There is little 
appreciable difference in percent species composition among 
the areas. Shorebird species may not prefer one region of 
the Illinois Valley over another for feeding and resting. 



Gulls and Terns 

The fall migration of gulls and terns occurs later than 
that of wading shorebirds. Usage of the 3 study areas by 
these birds increased during the October-December period each 
year from 1973 to 1978 (Table 9-7 ). Maximum use occurred 
during the January-March period indicating that many birds 
overwinter in the project area. Because gulls and terns 
feed on fish and can rest on the water, their presence is 
not limited to the August through December interval of mud 
flat exposure like wading shorebirds. Numbers decreased to 
a low point at the study areas between April and June. 

Total gull and tern use-days at the 3 study areas 
ranged from 96,700 in 1976 to 208,450 in 1975 (table 9-7). 
Weather conditions and changing populations may explain 
these year-to-year variations. No relationships between 
use-days and water levels (Table 9-12) are obvious, again 
emphasizing the independence of gulls and terns from re- 
liance upon mud flats. 

Of the 15 species of gulls and terns that were ob- 
served during the ground surveys at V»'eis , Chautauqua, 
and Meredosia lakes, only herring and ring-billed gulls can 
be considered common (Tables 9-3, 9-4, 9-5 ) . Relatively 
rare birds sighted at the study areas included long-tailed 
Jaegers ( Stercorar ius longicaudus ) , and Iceland ( Larus 
glaucoides ) , laughing (L . " atricilla ) , ivory ( Pagophi la 
eburnea ) , and Sabine's gulls (Xema sabini ) (see Table C-9 in 
Appendix C for status) . 

Lake Chautauqua received the most extensive use of the 
3 areas, averaging over 100,000 use-days by gulls and terns 
per year (Tables 9-3, 9-4, 9-5 ). Average use per year 
at Weis and Meredosia lakes ranged between 15,000 and 
20,000 use-days. Chautauqua also attracted twice as many 
different species as the other lakes. If these study areas 
are characteristic of their respective regions of the river. 
La Grange Pool supports the largest numbers and greatest 
diversity of gulls and terns, followed, in order, by Alton 



9-25 



Shorebirds 

and Peoria pools. Field observations indicate that the 
largest area of concentration in the Illinois Valley is 
Peoria Lake (Peoria Pool) . The great expanse of water and 
the abundance of fish for food probably attract the birds 
to this location. 

EFFECTS OF INCREASED DIVERSION 



Increased diversion of water into the Illinois River 
would almost certainly have detrimental effects on popu- 
lations of wading shorebirds. The level, gently sloping 
topography of the Illinois River backwater lakes creates 
excellent mud flats because large areas are low enough to 
remain covered with a thin film of water necessary for 
invertebrate development. The same flat terrain that makes 
these mud flats productive also makes them very precarious 
because a slight fluctuation in water levels is sufficient 
to alternately expose or inundate vast areas. 

In the Peoria Pool, a 15-cm (6-in) drop in the water 
level from the tree line exposes approximately 1,362 ha 
(3,400 acres) of mud flats for shorebird use (Table 5-2l). 
With the present rate of diversion, the water level falls 
an additional 15 cm (6 in) during the fall migration 
period approximately one out of every 2_years thus exposing 
a total of 2,175 ha (5,400 acres) of mud flats (Table 5-21). 
For a year such as 1971 with "normal" water conditions 
throughout the year and dry conditions during the 10 July- 
1 October shorebird migration period, the predicted 6,600- 
cfs diversion would maintain water levels at an average 
msl of 441.0 ft (Table 5-27) leaving only about 1,300 ha 
(3,400 acres) of mud flats exposed in the Peoria Pool. In 
a "dry" year with ample moisture during the migration period 
such as 1977 or in a "wet" year such as 1973, the predicted 
6,600-cfs diversion would inundate all of the mud flats. 
The predicted 10,000-cfs diversion would have placed the 
water level above the tree line in all of the model years, 
1971, 1973, and 1977 (Table 5-27). 

A 1.2-m (4-ft) drop in water levels from bankfull con- 
ditions (when water is up to the tree line) currently exposes 
almost 11,000 ha (27,000 acres) of mud flats in the La 
Grange Pool (Table 5-21). During one out of every 2 autumns, 
at least 9,600 ha (24,000 acres) of mud flats are exposed 
in the La Grange Pool, and usually 2,700 ha (6,800 acres) 
of mud flats are available every fall (Table 5-21). For a 
year such as 1971 with "normal" water conditions throughout 
the year and dry conditions during the 10 July-1 October 



9-26 



Shorebirds 



period of shorebird migration, the average msl with a pre- 
dicted 6,600-cfs diversion would be 433.3 ft (Table 5-27). At 
that water level, up to 2,700 ha (6,800 acres) of mud flats 
would be exposed (Table 5-21) . Under most other water con- 
ditions in the years modeled by the computer, both the 
predicted 6,600-cfs and the 10,000-cfs diversion rates 
would have raised water levels up to or beyond the tree line 
leaving the mud flats in the La Grange Pool completely 
inundated . 



With the increased diversion, the present mud flats in 
the Peoria and La Grange pools would thus essentially be 
unavailable as feeding and resting areas for wading shore- 
birds. Over a period of several decades, new mud flats may 
be formed slowly by a combination of woody vegetation die- 
off and sedimentation at the new shoreline. However, during 
the interim period, the possible absence of such an impor- 
tant natural resource as shorebirds would be a great loss 
both aesthetically and ecologically. 

Of greatest importance, however, is the physiological 
depletion that would be suffered by the shorebirds during 
migration if mud flats are unavailable because of inunda- 
tion. Large numbers of individuals utilize the Illinois 
River valley during fall migration. There are few other 
areas in the Midwest to provide the necessary feeding habitat 
for migrating shorebirds. The resulting effects on shore- 
bird survival would be important. With insufficient energy 
reserves, mortality would increase, particularly among 
immatures during the long flights over the Gulf of Mexico 
and Caribbean Sea. The impact on shorebird populations re- 
sulting from the elimination of mud flats would depend par- 
tially on the previous feeding conditions in the prairie 
wetlands of Canada and the Dakotas. Nevertheless, a lack of 
mud flats in the Illinois Valley would mean the removal of 
one traditional resting and feeding area for the shorebirds. 
Removal of such options decreases each shorebird's chance 
for survival during migration. 

The effects of an increased diversion on gulls and terns 
are expected to be negligible. If increased diversion results 
in increased fish populations, then gulls and terns may 
indirectly benefit. Their ability to rest on water, even 
though perch sites protruding from the water are preferred, 
eliminates their reliance on mud flats. 

In summary, an increased diversion of water into the 
Illinois River at 6,600 or 10,000 cfs would probably inundate 



9-27 
Shorebirds 



all of the mud flats that are now exposed each year by natural 
summer drawdowns. Usage of the project area by wading shore 
birds, which rely on the exposed mud flats for feeding and 
resting areas during migration, would probably decrease as 
mud flats became unavailable. The resulting changes in 
shorebird migrational patterns and the overall effects of 
these changes on their populations are difficult to predict. 
However, the loss of mud flats would pose additional hazards 
to their survival. Gulls and terns may be virtually 
unaffected . 



10-1 



CHAPTER 10: HERONS AND THEIR ALLIES 



Members of the family Ardeidae that are common in the 
Illinois Valley include tne great blue heron [ Ardea herodias ) , 
the great egret ( Casmerodius albus ) , the black- crowned night 
heron ( Nycticorax~liycticorax )~ and the green heron ( Butorides 
yirescens ) . Usage of the valley by cattle and snowy egrets 
( Bubulcus ibis , Egretta thula ) , least and American bitterns 
( Ixobrychus exi lis , Botaurus lent iginosus ) , little blue 
herons ( Florida caerulea ) , and yellow-crowned night herons 
( Nyctanassa violacea ) Ts ordinarily limited to foraging 
during the late summer and early fall, but it is probable 
that most of these species occasionally nest along the river. 

Because cattle and snowy egrets, little blue herons, 
bitterns, and yellow-crowned night herons normally nest 
singly or in small colonies, they are difficult to locate 
and a paucity of data results. Therefore, their probable 
habitat needs in the Illinois Valley are not entirely known. 
Little blue herons and snowy egrets are associated with the 
shallow waters of marshy areas for feeding and with dense, 
young stands of trees such as black willow and cottonwood 
for nesting. Cattle egrets which have been observed from 
Meredosia to Lacon during the nesting season (Graber et al., 
1978: 32) probably choose small trees such as ash, elm, 
persimmon, or pin oak for nesting. Because cattle egrets 
feed heavily on insects, pastures are favored feeding grounds. 
Lowland woods attract nesting yellow-crowned night herons 
and shallow, marshy areas provide their food. Least and 
American bitterns are especially secretive but it is likely 
that nesting by these species in scattered pockets of cat- 
tail and bulrush marsh is rare. 

Great blue herons (GB) , great egrets, black- crowned 
night herons (BCN) , and green herons are fairly abundant and 
also nest regularly in the Illinois Valley. In 1977, about 
one-fourth of the active nesting colonies of GB herons and 
great egrets in Illinois were located along the Illinois River 
(Graber et al., 1978: 8, 43). TablelO-1 presents the cen- 
suses and Figure 10-1shows the locations of these colonies 
during recent years. Four nesting colonies of BCN heron? 
may still exist in the project area (Graber et al., 1978: 55); 
however, less information about their status is available. 



10-2 



Table 10-1. Great Blue Heron, Great Egret, and Black-Crowned 
Night Heron Colony Locations and Censuses, 1973- 
1978.^ 





N 


u m b 


e 


r s of 


N e 


s t s 




Area 


1973 


1974 




1975 




1976 


1977 


1978 








Great Bl 


ue 


Heron 




De Pue 


20 


30 




45 




40 


40 


37 


Chillicothe 




40 




20 




25 


20 


27 


Pekin 


7 




















Clear Lake 


118 






62 






103 


143 


Grand Island 


pb 






55 




50 


65 


90 


Meredosia Lake 


P 





















Nutwood 








30 




10 







Grafton (Mo. si 


de) 









Great 


Eg 


3 

ret 






De Pue 


20 


15 




15 




10 


1 





Chillicothe 




1 




1 













Pekin 


2 





















Clear Lake 


30 






29 




15 


36 


47 


Grand Island 


P 






15 




10 





8 


Meredosia Lake 


P 




















Nutwood 
























Blac 


kj 


■Crowne 


d 1 


^ight 


Heron 




De Pue 


51 
















Pekin 




















Clear Lake 


109 












140 


180 


Naples 




> 10 















1973-1977: Graber et al . (1978). 1978: Clear Lake, Dr. 
R.G. Bjorklund, Bradley University; De Pue, Chillicothe, Pekin, 
M, Runkle, Illinois Department of Conservation. 

P - present but nests not counted. 



10-3 



LAKE MICHIGAN 




25 50 

IlLES 



50 

KILCWCTERS 



Figure 10-1. Heron colonies located within the proiect area 
in the Illinois River valley. 



10-4 
Herons 

Green herons may nest in every county of the state (Graber 
et al,, 1978: 20), but their nesting habits prohibit ef- 
fective censusing. Tributary streams and drainage ditches 
are probably the green heron's preferred nesting locations 
in the study area. 

Cottonwood, silver maple, and green ash are the primary 
tree species utilized for nesting by GB herons and great 
egrets. The birds prefer to nest in the largest trees 
available on large undisturbed sites averaging 608 ha 
(1,502 acres) (Graber et al., 1978: 5-7). Black-crowned 
night herons utilize a wide variety of upland and lowland 
tree species for nesting, but at the Pekin heronry, they 
preferred green ash (Bjorklund, 1975: 285). Marshes with 
61-91 cm (2-3 ft) of water also attract BCN herons, sug- 
gesting that the quality and proximity of foraging areas 
may be the most important factor in nest site selection. 
Green herons are inhabitants of sand or mud strands, 
prairie marshes, and bottomland woods. Edge situations with 
species such as willow, cottonwood, • silver maple, or button- 
bush are preferred for nesting. 

The shallow lagoons, backwaters, and marshes of the 
Illinois River valley provide food for the herons. The diet 
of three of the 4 common species of herons consists mainly 
of gizzard shad, carp, buffalo, and sunfish (Graber et al . , 
1978: 18, 48, 60). The green heron prefers sunfish, min- 
nows, crayfish, and insects (Graber et al., 1978: 25). 
During spring and early summer, the foraging areas must sup- 
port both the nesting adults and the progressively increasing 
nutritional demands of the young. By mid-July or the be- 
ginning of August, a second population of birds from the 
south, where the nesting cycle is completed much earlier, 
moves into the project area. Birds exhibiting this unusual 
migration pattern may come hundreds of kilometers northward 
to forage until cold weather forces them to return southward 
(Graber et al., 1978: 39). This second population, consisting 
mainly of little blue herons, great egrets, and snowy egrets, 
increases the demands upon food supplies. 

1978 FIELD INVENTORIES 



Censuses of the Illinois River heron and egret rookeries 
were conducted during May and June (Figure 10- 1 ) . Aerial 
counts of the De Pue, Chillicothe, and Pekin heronries were 
made by Max Runkle (Illinois Departmer.-^ of Conservation). 
Aerial censuses are feasible for counting great egret and 
GB heron nests which are located near the top of the "ee 



10-5 
Herons 

canopies, BCN herons, which have been found in the De Pue 
and Pekin colonies, nest below the tree canopy and may be 
overlooked by aerial observers. Dr. Richard Bjorklund 
(Bradley University) censused the Clear Lake rookery from 
the ground. The Grand Island Heronry was also censused from 
the ground by Illinois Natural History Survey staff. Ground 
censusing involves moving among the nest trees and checking 
each individual nest for current occupancy indicated by 
the presence of food remains, feathers, or excrement beneath 
it. Because GB herons and great egrets often nest in the 
same tree, care must be taken to differentiate between 
nests of the two species. Nests of the great egret are 
generally somewhat smaller than those of the GB heron and 
are lower in the tree. Presence of adult birds at the 
nest or visibility of young also aids in species differen- 
tiation. Census data from 1973 through 1977 and the 1978 
data are presented in Table 10-1 , 

Numbers of nesting GB herons have remained relatively 
stable at De Pue but the number of great egrets nesting at 
this site has dropped drastically (Table10-1), Although 
nesting at Chillicothe increased slightly in 1978, a 
slight downward trend occurred during the past 5 years. 
Great egrets are virtually gone from De Pue. Encouraging 
increases in great egret and GB heron numbers were documented 
in 1978 at the Clear Lake rookery. Black- crowned night 
herons also experienced a substantial increase in numbers 
at Clear Lake although data are limited to 2 years. Egret 
numbers at Grand Island in 1978 increased from the 1977 
figures but remained relatively stable when compared with 
previous years. However, GB herons made a significant in- 
crease in 1978 at Grand Island, 

Although nest numbers increased at some sites in 1978, 
the populations of GB herons, great egrets, and BCN herons 
appear to be experiencing an overall decline. The Illinois 
Endangered Species Act, passed in 1973, lists the great and 
snowy egrets, the BCN and little blue herons, and the 
American bittern among those in danger of extinction as 
breeding species in Illinois, An increasing incidence of 
nest colony abandonment by GB herons and great egrets has 
resulted in the desertion of approximately 10 sites between 
Beardstown and Starved Rock since 1900. Information on the 
green heron population in Illinois is scarce, but all data 
indicate that there has also been a serious decrease in 
their numbers during this century (Graber et al,, 1978: 22), 
Timber cutting, illegal hunting, hydrocarbon pollution, wind 
destruction of nests and young, and human disturbance during 
nesting are all contributing factors. Lumbering is especially 
threatening to GB herons and great egrets which require 
large nest trees in extensive tracts of undisturbed timber. 



10-6 



Herons 



EFFECTS OF INCREASED DIVERSION 

The effects upon herons and egrets of an increased 
diversion of water into the Illinois River may be both 
positive and negative. The primary nest tree species of 
GB herons, great egrets, BCN herons, and green herons 
are relatively tolerant of flooding. However, increased 
flooding frequency or duration may result in the death of 
nesting trees and the subsequent abandonment of the site. 
The extremely large trees preferred by GB herons and 
great egrets are somewhat sensitive to flooding regardless 
of species (Yeager, 1949: 43). Bjorklund (1975: 286) 
felt that protracted inundation of the Pekin heronry floor 
for two successive springs was the final factor causing 
abandonment of that site. 

Slightly higher water levels may create more shallow 
foraging areas for herons and egrets but water held to the 
tree line of the backwater lakes would be excessively deep 
for optimum feeding conditions. Heron populations are 
primarily dependent upon fish populations for food; there- 
fore, factors beneficial to fish, such as increased spawning 
areas, may indirectly aid herons. However, increased 
turbidity possibly caused by a greater volume of water may 
be detrimental to herons and egrets which depend on sight 
for feeding. In addition, some authorities believe that the 
concentration of fish caused by low water conditions in 
summer is important to foraging adult herons as the food 
requirements of the nestlings reach their peak (Graber et 
al., 1978: 8). 

Overall, an increased diversion is expected to be 
detrimental to herons and egrets in the Illinois River 
valley. Even minor detrimental effects may further 
jeopardize the precarious conditions of their papulations 
in the project area. 



n-1 



CHAPTER 11: BALD EAGLES, DOUBLE-CRESTED CORMORANTS, AND 
MISSISSIPPI KITES 



Three endangered species of avifauna occur in the 
Illinois Valley that merit special attention because of 
their close relationship to the river and its habitats. 
These species are the bald eagle ( Haliaeetus leucocephalus ) , 
the double- cres ted cormorant ( Phalacrocorax aur i tus ) , 
and the Mississippi kite ( Ictinia mississippiensis j . 



BALD EAGLE 



Wintering populations of endangered bald eagles 
begin to arrive in Illinois from the northern breeding 
grounds during the fall months. By January or February, 
eagle numbers peak at more than 1,000 individuals 
(Illinois Department of Conservation, 1979: 3) -- a 
sizeable number for a species in danger of extinction over 
much of its range. Major concentrations of eagles occur 
along the Mississippi and Illinois rivers but a segment 
of the population also disperses (at least temporarily) 
to various lakes and vaterways across the state. 

Fish such as shad, carp, and buffalo comprise the 
majority of the eagles' diet. Therefore, their activities 
center upon open water. In the project area, eagles 
generally find open water below dams on the river channel 
or around spring holes in the backwaters (Robert Crompton, 
personal communication). Shad congregate at these openings 
where they become available to eagles that are either 
standing on the ice around the hole or waiting on nearby 
tree perches (Southern, 1963: 46, 47). Occasionally, sick 
or dead waterfowl are eaten (Crompton, personal communica- 
tion) . Even though areas of open water become limited 
by midwinter, large numbers of eagles will not feed 
together for extensive time periods. This intolerance 
is probably a result of their aggressiveness and also 
their habit of stealing food from each other (Southern, 
1963: 46, 48). For preening or roosting, however, eagles 
often congregate in large trees. Sycamore and cotton- 
wood trees appear to be the preferred roost tree species. 



11-2 
Eagles etc. 



probably because of their broad horizontal limbs (Crompton, 
personal communication). Roosting sites are often located 
away from the river in sheltered ravines and may be 
frequented by 200-300 individuals. 

Eagles occupy their Illinois wintering grounds until 
about March when their numbers begin to gradually decline 
(Southern, 1963: 44). During April, the exodus to the 
breeding grounds is completed. 

1978 Field Inventory 

Weekly aerial counts of eagles inhabiting the 
Illinois River valley from September 1978 to January 1979 
were made by Robert Crompton. Census routes were flown 
between 0800 and 1700 hrs when the eagles were active. 
Approximately 751> of the eagles were detected by the 
aerial censuses. The fact that eagles remain in a mottled 
brown immature plumage until four years of age makes imma- 
tures less conspicuous than adults, particularly when 
perched in trees. Because of this plumage difference, 
more immatures are overlooked than adults. These counts, 
therefore, should be used only as an index to the total 
population for comparison among months and years, and not 
as the actual number of eagles present. 

Data on eagles counted by Crompton during Illinois 
Valley census flights for the winter of 1978-1979 and also 
for the two previous winters are presented in Table 11-1. 
The counts for all three winters have been totaled by 
age, averaged by month, and separated into four regions 
of the river. Averages for the various months and regions 
have been totaled to allow comparison between years. 

Arrival of eagles in the project area ranged from 
the last week of October for the winter of 1977-1978 to 
the second week of November for the winter of 1978-1979. 
For the winters of 1977-1978 and 1978-1979, the number 
of eagles reached a peak in December (Table 11-1). 

Wintering eagle numbers in Illinois have been on the 
increase since the 1940's. Graber and Golden (1960: 22,23) 
documented this increase twenty years ago and recent data 
indicate that it is still continuing (Table 11-1 ). A 
noticeably large iump in numbers occurred between the 
winters of 1977-1978 and 1978-1979. 



n-3 



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t-^ LO LO 

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r- to VD 



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1 1-4 



Eagles etc. 

The average percentage of immatures in the project 
area increased from 29b to 3A% during the past 3 years 
(Table 11-1 ). For most species of birds, the percentage 
of immatures in a population can be used to indicate the 
reproductive success of that population. Considering the 
extensive areas and time periods covered by the censuses, 
it may be possible to assume that these data can be used 
as such an indicator. 

During the three years considered, the largest seg- 
ment of the wintering eagle population resided in the 
La Grange Pool (Table 11-1 ). The next largest portion 
was found in the Peoria Pool. However, almost two-thirds 
of the eagles observed during the censuses were localized 
in the areas below dams (Crompton, personal communication). 
Some specific daytime perch sites that were favored include 
Plum Island below Starved Rock Lock and Dam, Meyer's 
Ditch near Lake Chautauqua, and Crane Lake. 

A population of up to 200 individuals has been 
regularly observed at Pere Marquette State Park, Jersey 
and Calhoun counties, Illinois (Terpening et al., 1975: 
52) . The feeding activity of the eagles was centered 
around the Six-mile Island area of Swan Lake (Crompton, 
personal communication). An additional unusual site was 
located in Havana at a towboat dock. Human activity at 
this location did not appear to disturb the eagles as 
they fed on fish stunned by the propellers of the tows or 
perched in an adjacent Cottonwood tree. 



Effects of Increased Diversion 

An increased diversion of water into the Illinois 
River may be partially beneficial and partially detrimental 
to wintering bald eagles. The most important detriment to 
wintering eagles may be the death of roosting trees as a 
result of flooding. Cottonwood and sycamore trees, the 
preferred roost tree species, are relatively tolerant of 
flooding. However, over-mature trees such as those needed 
by the eagles are more susceptible to prolonged inundation 
than smaller trees (Yeager, 1949: 43). Increased turbidity 
which may result from an enhanced flow of water could be 
a detriment to the eagles because they depend on sight to 
feed. The increased flow could be beneficial if it results 
in more open water areas for feeding. Aspects of increased 
water volume that benefit fish, the eagles' staple food 
item, may indirectly benefit overwintering eagles. However, 
it is presently difficult to predict whether or not the 
benefits of the increased diversion will outweigh any 



n-5 



Eagles etc 



detriments. Considering the endangered status of the bald 
eagle, it is important that the increased diversion is not 
harmful to the wintering populations in Illinois. 



DOUBLE -CRESTED CORMORANTS 



Until the mid-1950's, the double- cres ted cormorant was 
a common migrant and a fairly common nester in the 
Illinois River valley (Smith and Parmalee, 1955: 9). 
Waves of cormorants migrating between their breeding 
grounds centered in southern Canada and their wintering 
grounds along the Gulf Coast passed through the valley 
each fall. A count made on 16 October 1950 revealed an 
estimated 15,000 migrants in the project area between 
Spring Valley and Meredosia. On 7 October 1940 and 9 
October 1949, huge single flights of 12,000 and 9,500 
cormorants, respectively, were observed as they passed 
Havana (Mills et al., 1966: 21). By 1958, these great 
passages of cormorants had dwindled to a small flight 
of 300 individuals. The reasons for the decline experi- 
enced by cormorant populations are unknown, but the sud- 
denness and severity of the decline suggest that possibly 
pesticides may have been a primary cause. 

Cormorants once nested in conjunction with herons at 
the major heronries of the Illinois Valley, but only a 
single nesting colony, located on islands in the Missis- 
sippi River north of St. Louis, remains in the state 
(Graber and Graber, 1976; 10). Human disturbance was 
probably a factor in the decline of nesting cormorants 
because entire nesting colonies located in the dead trees 
of isolated islands or swamps were destroyed by commercial 
fishermen. Scarcity of suitable nesting habitat probably 
also contributed to their demise because cormorants prefer 
undisturbed stands of dead trees that are flooded for at 
least the initiation of their nesting season. The dead 
trees are useful for nesting only as long as they retain 
sufficient branches to support nests. 

Weekly aerial surveys of cormorants were conducted in 
the Illinois Valley each fall and spring from 1974 through 
1978 and in the spring of 1979. The counts, made by 
Robert D. Crompton, Illinois Natural History Survey, are 
presented in Table 11-2 . No cormorants were sighted be- 
tween 1966 and 1973, However, beginning in 1974, the 
censuses have uncovered an increasing number of migrants. 
Fall migration through the project area appears to begin 



11-6 



Table 11-2. Spring and Fall Aerial Censuses of Double- 
Crested Cormorants in the Illinois River Valley, 
1974-1979.^ 



Areas 



Date 



10-7 
1 1-5 

n-12 

11-19 
11-25 

Total 



Peoria 


La 


Grange 


Pool 




Pool 




1974 












135 




118 


152 




103 


205 




155 







65 



Alton 
Pool 



108 

30 





Total 
Number 



9 
261 
363 
390 

65 



492 



441 



155 



1 ,088 



Total 



182 



1975 



10-6 





41 


10-13 


22 


37 


10-20 


38 


104 


11-4 





47 


11-11 


76 


40 


11-17 


46 


44 



313 



13 


54 


25 


84 


45 


187 


8 


55 


24 


140 


43 


135 



158 



653 



Total 



235 



1976 



4-7 


105 


135 


4-13 


105 


52 


10-4 


25 


34 



221 






240 





157 





59 



456 



Total 



520 



1977 



4-12 


105 


270 


9-20 


55 


26 


9-27 


129 


62 


10-4 


78 


126 


10-11 


96 


86 


10-19 


57 


63 



633 



40 


415 


29 


110 


35 


226 


43 


247 


33 


215 





120 



180 



1 .333 



Sheet 1 of 2 



11-7 



Table n-2concluded -- Cormorant Censuses 







Areas 








Peoria 


La 


I Grange 


Alton 


Total 


Date 


Pool 




Pool 


Pool 


Number 




197£ 






4-7 


74 




140 


46 


260 


4-13 


90 




108 


13 


211 


9-19 


57 




52 


18 


127 


9-26 


75 




79 


20 


174 


10-2 


56 




146 


30 


232 


10-9 


90 




137 


66 


293 


10-30 


80 




49 


34 


163 



Total 522 711 227 1,460 

1979 

29 94 

77 583 



3-19 





65 


3-27 


182 


324 


4-5 


181 


79 


4-13 


144 


92 



30 290 

40 276 

Total 507 560 176 1,243 



^Censuses conducted by Robert D. Crompton, Illinois Natural 
History Survey. 

Only censuses during which cormorants were sighted are 
listed. 

''Aerial censuses of the Upper Pools segment of 

the Illinois River were only conducted during 1976, 1977, 

and 1978. No cormorants were sighted during these flights. 



Sheet 2 of 2 



11-8 
Eagles etc. 



between mid-September and the first part of October and 
may continue into November. Cormorants were sighted during 
their spring migration in only four of the past 6 years 
(Table 11-2). 

Cormorants moving through the project area feed upon 
fish, eels, crustaceans, and other large aquatic organisms 
(Terpening et al., 1975: 49). The preference shown by 
cormorants for areas in the Peoria and La Grange Pools 
as opposed to areas in the Alton Pool corresponds to the 
abundance of backwaters available for feeding sites along 
the upper reaches of the river (Table 11-2). 

An increased diversion of water into the Illinois River 
would probably have negligible effects on cormorants be- 
cause usage of the project area by these birds is currently 
limited to feeding and resting during their fall and spring 
migration. If higher water levels favor fish and other 
aquatic organisms, then cormorants may benefit slightly 
by an increase in food supply. Death of bottomland timber 
that could result from prolonged inundation should not be 
detrimental to future nesting by cormorants because of 
their preference for dead trees as nesting sites. 



MISSISSIPPI KITE 



The Illinois breeding population of Mississippi kites 
has been in danger of extirpation since the 1950's 
(Smith and Parmalee, 1955: 19). Graber and Graber (1976: 
11, 12) believe this small population, that appears to be 
centered along the Mississippi River south of St. Louis, 
may be completely isolated from the substantial popula- 
tions to the south and west, thus making it an endemic 
population. 

In the project area, Mississippi kites have been 
observed as far north as Havana (Gates, 1911: 25; Smith 
and Parmalee, 1955: 19). Summer sightings of 4 indi- 
viduals at the Sanganois Conservation Area (Mason and 
Cass counties) during 1978 (Richard Sandburg, personal 
communication) suggest that the kites may possibly be 
nesting in the Illinois Valley, Research on 5 pairs of 
Mississippi kites that nested in Union County, Illinois, 
revealed that nests are placed near large openings in 
extensive tracts (83-372 ha; 205-919 acres) of mature 
bottomland timber. Sycamore, sweetgum, and cottonwood 
were the preferred nest tree species (Hardin et al.. 



n-9 



Eagles etc 



1977: 342). The kites were observed to forage along levee 
roads bordered by annuals or in fallow fields and woods 
where they captured cicadas, grasshoppers, toads, beetles, 
butterflies, and dragonflies (Hardin et al., 1977: 344, 
345) . 



b o 1 1 om 

their 

habita 

reprod 

clutch 

situat 

of wat 

death 

bottom 

could 

kites 



ecau 
land 
ende 
t as 
ucti 
siz 
ion. 
er i 
of n 
land 
be a 
are 



s e Miss 
timber 
mic 111 
a resu 
ve pote 
e also 

A pos 
nto the 
es ting 

forest 
f fected 
dif f icu 



issippi kites need extensive tracts of 

for nest sites, a primary threat to 
inois population is the loss of nesting 
It of lumbering and clearing. Low 
ntial resulting partly from a small 
leaves the population in a precarious 
sible effect of an increased diversion 

Illinois River on kites may be the 
trees following prolonged inundation of 
The amount of bottomland timber that 
and the resulting impact on Mississippi 
It to predict. 



12-1 



CHAPTER 12 : OTHER AVIFAUNA 



Two hundred eighty-five species of birds belonging to 
17 taxonomic orders have either been observed in the Illinois 
River valley during recent field inventories or are expected 
to occur there. Of these, 4 orders and selected individual 
species have been given special consideration in other sec- 
tions of this report. Because of their smaller size or less 
intimate association with the river, the remaining orders 
will be discussed in this section. 



ORDER GAVI I FORMES 



Loons occur in the project area only occasionally 
during migration. These highly aquatic birds feed on fish, 
crustaceans, insects, reptiles, and plant parts which they 
obtain by diving (Bent, 1946: 53). Adaptations for aquatic 
life render loons almost completely helpless on land and 
they rarely go ashore. 



ORDER PODICIPEDIFORMES 



Horned ( Podiceps auri tus ) and pied-billed grebes 
( Podi lymbus podiceps ) commonly migrate through the Illinois 
River valley singly or in small groups. Fish, amphibians, 
crustaceans, insects, and vegetable matter comprise the 
diet of the submarine- like grebes (Robbins et al., 1966: 20) 
Like loons, grebes are highly aquatic and are rarely found 
on land. 



ORDER FALCONIFORMES 



A wide variety of raptors inhabits the project area. 
Large trees in forest habitats provide possible nest sites 
for the 9 species that breed in the valley and roost sites 
for 4 species of winter residents. Most of the hawks and 



12-2 
Other Avifauna 



the golden eagle ( Aqui la chrysaetos ) feed on insects, rep- 
tiles, birds, or small mammals which they capture in wooded 
and open areas (Robbins et al., 1966: 64). Turkey vultures, 
however, ( Carthartes aura ) scavenge for carrion (Robbins et 
al., 1966: 64). Osprey ( Pandion haliaetus ) , which occasionally 
move through the project area, feed entirely upon fish that 
they catch in the river backwaters (Bent, 1937: 366). The 
populations of most osprey, diurnal hunters which are 
highly adapted for their flesh-eating habits, have declined 
in recent years as a result of shooting and habitat destruc- 
tion (Graber and Golden, 1960: 21). 



ORDER GALLIFORMES, FAMILY PHASIANIDAE 



The project area is of secondary importance to the bob- 
white ( Colinus virginianus ) and the ring-necked pheasant 
( Phasianus colchicus ) . Both species nest in brushy old 
fields and forage for waste grain, seeds, berries, and 
insects (Robbins et al., 1966: 90). Therefore, usage of 
riverine areas is probably limited. Pheasants are completely 
absent from the Illinois River valley south of Cass County 
(La Grange Pool) (Labisky, 1975: 8). 



ORDER GRUIFORMES, FAMILY RALLIDAE 



During their migration, a small group of marsh birds, 
collectively referred to as rails, is closely associated 
with the backwaters of the Illinois River. The secretive 
habits of most of these species make them quite inconspicuous 
in the project area. The American coot ( Fulica americana ) , 
which migrates through the Illinois River valley in huge 
flocks each fall and spring, is an exception to the rule. 
The diet of rails consists of earthworms, snails, crayfish, 
insects, and seeds found in shallow water (Bent, 1926: 263, 
296, 307, 363). The accelerating loss of marsh habitat 
poses a threat to the continued usage of the Illinois Valley 
by these unique birds. 

ORDERS COLUMBIFORMES AND CUCULI FORMES 

Riverine habitats are probably not of the greatest im- 
portance to birds of these orders, yet some species probably 
occur frequently in the project area. The mourning dove 



12-3 
Other Avifauna 



( Zenaidura macroura ) nests near water in woodland edge situa- 
tions and feeds on cultivated grains and seeds. Black and 
yellow-billed cuckoos ( Coccyzus americanus and C. ery thro - 
pthalmus , respectively) nest in woods and brush near outbreaks 
of tent caterpillars, their staple food (Robbins et al., 
1966: 154 , 158). Pigeons or rock doves ( Columbia livia ) 
occur 'in the project area only in association 

with man's habitations. 



ORDER STRIGIFORMES 

Members of this order are probably quite common in the 
project area, but they are inconspicuous because of their 
nocturnal habits. Owls are hunters that feed on a variety 
of small birds, mammals, reptiles, and amphibians. Less 
frequently, fish and insects are eaten (Bent, 1938: 250, 
306). Most of the species found in the Illinois Valley are 
permanent residents that nest in natural tree cavities or 
cavities constructed by woodpeckers. Of all the owls, the 
barred owl ( Strix varia ) is probably the most typical species 
in the bottomland forest and, therefore, the species most 
affected by changes in the Illinois River. Screech ( Otus 
asio ) and great-horned owls ( Bubo virginianus ) are also 
common. The screech owl prefers open timber and the great- 
horned owl occurs along the margins of the bottomland forest 
because of its upland feeding habits. The population records 
for barred owls are incomplete but the numbers have decreased 
in recent years. Population trends were not evaluated for 
other species of owls because records are incomplete (Graber 
and Golden, 1960: 21) . 

ORDER CAPRIMULGIFORMES 



Two species belonging to this order are present in the 
Illinois Valley but are overlooked by most censuses because 
of their nocturnal or crepuscular habits. The whip-poor-will 
( Caprimulgus voci ferus ) lays its eggs on the ground in wooded 
habitat and feeds on insects that it captures in flight 
(Pough, 1946: 24). Common nighthawks ( Chordei les minor ) 
nest almost exclusively in man's habitations, but the abun- 
dance of insects occurring near bodies of water probably 
attracts these birds to the project area for feeding. 



12-4 
Other Avifauna 

ORDER APODI FORMES 



The ruby- throated hummingbird ( Archilochus colubris ) 
frequents edges of forests and weedy areas (Bohlen, 1978: 
78). It nests in trees or shrubs. Nectar extracted from 
flowers is a primary food for hummingbirds. Chimney swifts 
( Chaetura pelagica ) nest in man's habitations but probably 
visit the project area to feed on insects (Pough, 1946: 170) 



ORDER CORACIIFORMES, FAMILY ALCEDINIDAE 



Belted kingfishers ( Megaceryle alcyon ) are important 
permanent residents of the Illinois Valley streams and 
backwaters. Kingfishers share with terns the unique habits 
of hovering and diving headlong into water (Robbins et al., 
1966: 178). The major food items of kingfishers are fish, 
crayfish, shellfish, and insects that are captured in the 
birds' sharp beaks. Nesting takes place near water in 
chambers excavated from steep banks. Kingfishers play a 
desirable and important role in stream ecology by reducing 
heavy populations of small fish (Pough, 1946: 35). 



ORDER PI CI FORMES 



Woodpeckers are among the most common residents of the 
Illinois Valley bottomland forests. A wide variety of foods 
ranging from insects to fruits and acorns are consumed, but 
ants appear to be the favorite food item for the majority 
of the species (Pough, 1946: 38). Cavities excavated in 
living or dead trees provide nest sites. Unlike most wood- 
pecker species, the secretive pileated woodpecker ( Dryocopus 
pileatus ) has the added nesting requirement of extensive 
tracts of heavily wooded bottomland forest. It rarely 
finds such habitat anywhere in the state except along the 
Illinois and Mississippi rivers (Bohlen, 1978: 79). Com- 
petition for nest cavities by starlings ( Sturnus vulgaris ) 
appears to be a principal cause of population declines in 
some woodpecker species (Graber and Graber, 1963: 503) . 



12-5 



Other Avifauna 



ORDER PASSERI FORMES 



This order encompasses a tremendous number of birds 
with a broad spectrum of food and habitat requirements. 
Although a large percentage of the birds in the project 
area are passerines, their presence is often less obvious 
as a result of their relatively small size. The status of 
the various perching birds in the Illinois Valley ranges 
from permanent, summer, or winter resident to transient 
visitor. 

Bottomland forests provide habitat for the largest 
numbers and greatest diversity of passerines in the project 
area. Families such as Tyrannidae, Corvidae, Paridae, 
Sittidae, Certhiidae, Sylviidae, Turdidae, Vireonidae, 
Parulidae, Icteridae, and Thraupidae occur in the bottom- 
land forests. Brushy edge habitats attract members of the 
families Mimidae, Trog lody tidae , Bombyci 1 lidae , Laniidae, 
Vireonidae, and Parulidae. The families Hirundinidae , 
Troglody tidae , Parulidae, and Icteridae all contain 
species that are marsh inhabitants or are closely asso- 
ciated with water. Starlings, purple martins ( Progne 
subis ) , and house sparrows ( Passer domesticus ) , all of 
which occur primarily in association with man's dwellings, 
probably make limited use of the project area. Fringi llidae , 
the most diverse family of passerine birds, has members that 
occur throughout the various habitats in the project 
area. 

The majority of passerines in the Illinois V^alley, 
particularly the woodland inhabitants, are insectivorous 
(Gates, 1911: 17). Some species feed primarily or secon- 
darily on seeds, fruits, and mast crops. Birds of the 
family Turdidae rely heavily on earthworms for food, whereas 
members of the Corvidae are omnivores. Shrikes ( Lanius spp.) 
are unique among passerines because of their raptorial 
habits . 

Although birds of the order Passeriformes are often 
heard more than they are seen, they are an integral part of 
the floodplain ecosystem. 

A listing of the birds that may occur in the project 
area is presented in Table C-9 in the appendices. 



12-6 



Other Avifauna 

FIELD INVENTORIES 



Censuses of the relatively small, inconspicuous birds 
considered in this section are practically nonexistent for 
the project area. Audubon Christmas counts of permanent 
and winter residents and a summer census of permanent and 
summer residents by Drs. Richard and Jean Graber were 
available. Most of the transient species omitted in these 
censuses are given special consideration in other sections 
of this report. Some strictly nocturnal species of birds, 
such as owls and goatsuckers, were undoubtedly overlooked 
in these censuses. 

Data from Audubon Christmas bird counts conducted in 

late December of 1973-1977 at 2 locations in each of the 4 

regions of the river were used (Figures 3-1 and 12-1 ). 

Five-year averages (1973-1977) of the number of birds 

sighted per party-hour at the 8 census sites and the number 

of average sightings for the 4 river regions are summarized 
in Tables 12-1 throuph 12-4. 

House sparrows, starlings, dark-eyed juncos ( Junco 
hyemalis ) , tree sparrows ( Spi zella arborea ) , red-winged 
blackbirds ( Agelaius phoenicus ) , common crows ( Corvus 
brachyrhynchos ) , and common grackles ( Quiscalus quiscula ) 
were the most abundant winter residents in all 4 regions 
of the river. In the upper pools, rock doves, horned larks, 
mourning doves, black-capped chickadees ( Parus atricapil lus ) , 
cardinals ( Cardinalis cardinalis ) , and snow buntings 
( Plectrophenax nivalis ) were sighted more than once per 
party-hour (Table 12-1). American goldfinches ( Spinus 
tristis ) , cardinals, black-capped chickadees, blue jays 
( Cyanocitta cristata ) , mourning doves, song sparrows 
( Melospi za melodia ) , downy woodpeckers ( Dcndrocopos pubes - 
cens ) , tufted titmice ( Parus bicolor ) , bobwhites, horned 
larks, rock doves, white-breasted nuthatches ( Si tta carol - 
inensis ) , and Lapland longspurs ( Calcarius lapponicus ) , 
respectively, were the most abundant species (over 1 indivi- 
dual sighted/party-hour) in the Peoria Pool (Table 12-2). 
The most common winter species in the La Grange Pool in- 
cluded American goldfinches, cardinals, blue jays, black- 
capped chickadees, mourning doves, horned larks, brown- 
headed cowbirds ( Molothrus ater ) , swamp ( Melospiza georgiana ) 
and song sparrows, American robins ( Turdus migratorius ) , 
bobwhites, downy woodpeckers, rock doves, and red-bellied 
woodpeckers ( Centurus carolinus ) (Table 12-3). Abundant 
species observed in the Alton Pool are largely permanent 
residents. Species sighted more than once per party-hour 



12-7 



LAW MICHIGAN 




25 SO 

MILES 



50 

KILOMETERS 



Figure 12-1. Summer breeding bird census and Audubon 

Christmas bird count locations within the 
project area of the Illinois River valley 



12-8 



Table 12-1. Five-year Average of Birds Sighted per Party-Hour 
in December for Two Areas in the Upper Po'o^ls, 
1973-1977. ^ 



c • b 
Species 



Number of Birds per Party-Hour 



Horned grebe 
Pied-billed grebe 
Goshawk 

Sharp-shinned hawk 
Cooper's hawk 
Red-tailed hawk 
Red-shouldered hawk 
Rough- legged hawk 
Marsh hawk 
American kestrel 
Bobwhite 

Ring-necked pheasant 
Rock dove 
Mourning dove 
Screech owl 
Great-horned owl 
Barred owl 
Long-eared owl 
Belted kingfisher 
Common flicker 
Red-bellied woodpecker 
Red-headed woodpecker 
Yellow-bellied sapsucker 
Hairy woodpecker 
Downy woodpecker 
Horned lark 
Blue jay 
Common crow 

Black-capped chickadee 
Tufted titmouse 
White-breasted nuthatch 
Red-breasted nuthatch 
Brown creeper 
Winter wren 
Carolina wren 
Long-billed marsh wren 
Mockingbird 
Brown thrasher 
American robin 
Hermit thrush 



Morris- 


Starved Rock' 


i 


Wilmington 


State Park 


Mean 


0.006 


0.004 


0.004 


0.035 





0.013 


0.029 


0.004 


0.013 


0.006 


0.011 


0.009 


0.018 





0.007 


0.368 


0.084 


0.193 


0.006 





0.002 


0.263 


0.252 


0.256 


0.058 


0.015 


0.031 


0.310 


0.109 


0.187 


0.339 


0.288 


0.308 


0.854 


0.401 


0.575 


9.550 


6.942 


7.944 


2.988 


0.785 


1 .631 


0.164 


0.007 


0.067 


0.053 


0.007 


0.025 





0.007 


0.004 


0.047 





0.018 


0.111 


0.029 


0.061 


0.228 


0.292 


0.267 


0.175 


0.307 


0.256 


0.269 


0.405 


0.353 


0.193 


0.022 


0.088 





0.128 


0.079 


0.936 


0.942 


0.939 


2.263 


5.431 


4.213 


0.918 


0.770 


0.827 


2.404 


3.055 


2.804 


1 .520 


1 .580 


1 .557 


0.094 


0.748 


0.497 


0.152 


0.551 


0.398 


0.053 


0.036 


0.043 


0.556 


0.120 


0.288 


0.012 


0.040 


0.029 


0.105 


0.080 


0.090 


0.012 





0.004 





0.011 


0.007 





0.007 


0.004 


0.088 





0.034 





0.004 


0.002 



Sheet 1 of 2 



12-9 



Table 12- 1c on eluded 



Five-Year Average Birds, Upper Pools 



Number of Birds per Party-Hour 



Species 

Eastern bluebird 
Golden-crowned kinglet 
Ruby-croAvned kinglet 
Cedar waxwing 
Northern shrike 
Loggerhead shrike 
Starling 

Yellow-rumped warbler 
House sparrow 
Eastern meadowlark 
Red-winged blackbird 
Rusty blackbird 
Brewer's blackbird 
Common grackle 
Brown-headed cowbird 
Cardinal 

Evening grosbeak 
Purple finch 
Pine siskin 
American goldfinch 
Rufous-sided towhee 
Dark-eyed junco 
Tree sparrow 
Field sparrow 
Harris ' sparrow 
White-crowned sparrow 
White- throated sparrow 
Fox sparrow 
Swamp sparrow 
Song sparrow 
Lapland longspur 
Snow bunting 

Total 



>lorris- 


Starved Rock 


u 


V^ilmington 


State Park 


Mean 


0.035 


0.007 


0.018 


0.105 


0.004 


0.043 


0.018 





0.052 


0.129 


0.044 


0.076 


0.023 





0.009 





0.007 


0.004 


35.778 


15.960 


23.575 


0.025 


0.007 


0.013 


24.538 


27.124 


26.130 


0.146 


0.091 


0.112 


0.515 


3.628 


2.261 


0.006 


0.069 


0.045 


0.006 





0.002 


0.491 


0.347 


0.402 


0.228 


0.208 


0.216 


1 .444 


1 .248 


1 .324 


0.064 


0.007 


0.029 


0.064 


0.066 


0.065 


0.269 


0.007 


0.108 


0.895 


0.620 


0.726 


0.006 


0.004 


0.004 


12.58 5 


12.537 


12.555 


13.433 


4.139 


7.710 


0.123 


0.029 


0.065 


0.006 





0.002 


0.222 


0.069 


0.128 


0.298 


0.047 


0.144 


0.029 


0.106 


0.054 


0.532 


0.077 


0.252 


1 .485 


0.296 


0.753 


0.760 


0.007 


0.004 





1 .818 


1.119 


119.433 


92.047 


102.127 



Audubon Christmas bird counts, 1973-1977. 

Species considered separately elsewhere in the report are 
not included in this listing. 

Q 

Area 1 in Figure 12-1. 
Area 2 in Figure 12-1. 



Sheet 2 of 2 



12-10 



Table 12-2. Five-year Average of Birds Sighted per Party-Hour J 
in December for Two Areas in Peoria Pool, 1973-1977.' 



Species 

Horned grebe 
Pied-billed grebe 
Sharp- shinned hawk 
Cooper's hawk 
Red-tailed hawk 
Red-shouldered hawk 
Rough- legged hawk 
Marsh hawk 
Osprey 

American kestrel 
Bobwhi te 

Ring-necked pheasant 
Wild turkey 
Rock dove 
Mourning dove 
Screech owl 
Great-horned owl 
Barred owl 
Long-eared owl 
Belted kingfisher 
Common flicker 
Pileated woodpecker 
Red-bellied v.'oodpecker 
Red-headed woodpecker 
Yellow-bellied sapsucker 
Hairy woodpecker 
Downy woodpecker 
Horned lark 
Blue jay 
Common crow 

Black-capped chickadee 
Tufted titmouse 
White-breasted nuthatch 
Red-breasted nuthatch 
Brown creeper 
Winter wren 
Carolina wren 
Mockingbird 
Brown thrasher 
American robin 
Eastern bluebird 
Golden-crowned kinglet 
Ruby-crowned kinglet 



Number of Birds per Party-Hour 
Princeton^ Chillicothe" Mean 






0.002 


0.001 





0.002 


0.001 


0.013 





0.004 


0.004 


0.005 


0.004 


0.234 


0.297 


0.274 


0.004 





0.001 


0.126 


0.245 


0.202 


0.021 


0.028 


0.025 





0.002 


0.001 


0.067 


0.093 


0.084 


0.711 


1 .633 


1 .303 


0.084 


0.023 


0.045 


0.013 





0.004 


1 .414 


0.984 


1 .138 


1 .234 


2.054 


1 .760 





0.002 


0.001 


0.004 


0.012 


0.009 


0.013 





0.004 





0.002 


0.001 


0.042 


0.044 


0.043 


0.410 


0.308 


0.345 





0.005 


0.003 


0.778 


0.815 


0.802 


1 .008 


0.596 


0.744 


0.042 


0.002 


0.016 


0.259 


0.180 


0.208 


1 .686 


1 .444 


1 .531 


0.519 


1 .603 


1 .214 


2.059 


1 .745 


1 .858 


2.891 


2.738 


2.793 


2.699 


4.756 


2.928 


1 .834 


1 .336 


1 .514 


1 .381 


0.862 


1 .048 


0.046 


0.009 


0.022 


0.084 


0.079 


0.081 


0.029 


0.012 


0.018 


0.167 


1 .149 


0.798 


0.017 


0.1 17 


0.081 


0.004 


0.005 


0.004 


0.017 


0.035 


0.028 


0.033 


0.037 


0.036 


0.021 


0.051 


0.040 





0.002 


0.001 



Sheet 1 of 2 



12-11 



Table 12-2concluded -- Average Birds, Peoria Pool 



Species 

Cedar waxwing 
Starling 
House sparrow 
Eastern meadowlark 
Red-winged blackbird 
Rusty blackbird 
Brewer's blackbird 
Common grackle 
Brown-headed cowbird 
Cardinal 
Dickcissel 
Evening grosbeak 
Purple finch 
Common redpoll 
Pine siskin 
American goldfinch 
Rufous-sided towhee 
Sharp-tailed sparrow 
Savannah sparrow 
Vesper sparrow 
Dark-eyed junco 
Tree sparrow 
Chipping sparrow 
Field sparrow 
White-crowned sparrow 
White- throated sparrow 
Fox sparrow 
Lincoln's sparrow 
Swamp sparrow 
Song sparrow 
Lapland longspur 
Snow bunting 

Total 



Number of Birds per Party-Hour 
Princeton*- Chillicothe" Mean 



0.013 


0.014 


0.013 


28.088 


25.727 


26.573 


37.992 


29.612 


32.615 


0.113 


0.145 


0.133 


21 .456 


10.995 


14.744 


0.054 


0.248 


0.178 


0.033 


0.026 


0.028 


0.669 


4.227 


2.952 


0.322 


0.320 


0.321 


2.510 


3.421 


3.094 


0.004 





0.001 


0.301 


0.070 


0.153 


0.439 


0.075 


0.205 





0.028 


0.018 


0.259 





0.093 


1 .410 


2.336 


2.004 


0.008 


0.005 


0.006 


0.004 





0.001 





0.002 


0.001 





0.002 


0.001 


12.703 


15.215 


14.315 


8.364 


10.939 


10.016 





0.002 


0.001 


0.117 


0.019 


0.054 


0.163 


0.049 


0.090 


0.197 


0.079 


0.121 


0.013 


0.026 


0.021 





0.002 


0.001 


0.544 


1 .168 


0.945 


1 .285 


1 .942 


1 .706 


0.008 


1 .556 


1 .001 





0.005 


0.003 


37.037 


131 .569 


132.426 



^Audubon Christmas bird counts, 1973-1977. 

Species considered separately elsewhere in the report are 
not included in this listing. 

Area 3 in Figure 12-1 . 
Area 4 in Figure 12-1 . 



Sheet 2 of 2 



12-12 



Table 12-5. Five-year Average of Birds Sighted per Party-Hour 

in December for Two Areas in La Grange Pool, 1973-197'. 



Number of Birds per Party-Hour 



Species 

Horned grebe 
Pied-billed grebe 
Goshawk 

Sharp- shi nned hawk 
Cooper's hawk 
Red-tailed hawk 
Red-shouldered hawk 
Broad-winged hawk 
Rough- legged hawk 
Golden eagle 
Ferruginous hawk 
Marsh hawk 
American kestrel 
Bobwhi te 

Ring-necked pheasant 
Virginia rail 
Rock dove 
Mourning dove 
Screech owl 
Great-horned owl 
Barred owl 
Long-eared owl 
Short-eared owl 
Saw-whet owl 
Belted kingfisher 
Common flicker 
Pileated woodpecker 
Red-bellied woodpecker 
Red-headed woodpecker 
Yellow-bellied sapsucker 
Hairy woodpecker 
Downy woodpecker 
Least flycatcher 
Horned lark 
Blue jay 
Common crow 

Black-capped chickadee 
Tufted titmouse 
White-breasted nuthatch 
Red-breasted nuthatch 
Brown creeper 
Winter wren 
Carolina wren 



Chautauqua 






National 


Crane Lake- 


Mean 


Wildl. Ref.c 


Sangamon 


0.004 





0.002 


0.011 





0.005 


0.007 


0.014 


0.011 


0.022 


0.021 


0.021 


0.018 


0.046 


0.032 


0.302 


0.479 


0.392 


0.018 





0.009 


0.004 





0.002 


0. 167 


0.095 


0.131 





0.046 


0.023 





0.004 


0.002 


0.113 


0.120 


0.116 


0.171 


0.116 


0.143 


0.964 


1 .940 


1 .460 


0.080 


0.556 


0.322 


0.007 





0.004 


1 .767 


0.560 


1 .154 


1 .400 


3.842 


2.640 


0.044 


0.120 


0.082 


0.044 


0.246 


0.147 


0.055 


0.081 


0.068 





0.011 


0.005 


0.007 





0.004 


0.004 





0.002 


0.051 


0.049 


0.050 


0.349 


1 ,282 


0.823 


0.033 


0.144 


0.089 


0.767 


1 .401 


1 .089 


0.913 


0.831 


0.871 


0.018 


0.092 


0.055 


0.287 


0.363 


0.326 


1 .047 


1 .496 


1 .275 





0.004 


0.002 


0.996 


4.116 


2.581 


2.964 


3.430 


3.200 


12.651 


8.585 


10.585 


3.190 


2.458 


2.818 


0.924 


0.880 


0.902 


0.651 


1 .123 


0.891 


1 .858 


0.162 


0.174 


0.324 


0.137 


0.229 


0.025 


0.074 


0.050 


0.131 


0.542 


0.340 



Sheet 1 of 2 



12-13 



Table12-3concluded -- Average Birds, La Grange Pool 



Number of Birds per Party-Hour 

Chautauqua 
National Crane Lake- 
Species Wildl. Ref.^ Sangamon ^ Mean 

Mockingbird 
Brown tlirasher 
American robin 
Eastern bluebird 
Golden-crowned kinglet 
Ruby-crowned kinglet 
Cedar waxwing 
Loggerhead shrike 
Starling 

Yellow-rumped warbler 
House sparrow 
European tree sparrow 
Eastern meadowlark 
Red-winged blackbird 
Rusty blackbird 
Common grackle 
Brown-headed cowbird 
Cardinal 

Evening grosbeak 
Purple finch 
Pine siskin 
American goldfinch 
Red crossbill 
White-winged crossbill 
Rufous-sided towhee 
Sharp-tailed sparrow 
Vesper sparrow 
Dark-eyed junco 
Tree sparrow 
Field sparrow 
Harris' sparrow 
White-crowned sparrow 
White- throated sparrow 
Fox sparrow 
Swamp sparrow 
Song sparrow 
Lapland longspur 
Snow bunting 

Total 

^Audubon Christmas bird counts, 1973-1977. 

"Species considered separately elsewhere in this report are 

not included in this listing. 



0.033 


0.243 


0.140 


0.007 


0.004 


0.005 


3.215 


0.158 


1 .662 


0.018 


0.085 


0.052 


0.473 


0.468 


0.470 


0.015 


0.063 


0.039 


0.164 


0.197 


0.181 


0.004 


0.007 


0.005 


51 .596 


14.778 


32.891 


0.022 


0.183 


0.104 


22.389 


31 .806 


27.174 


0.011 


1 .768 


0.903 


0.145 


0.197 


0.172 


6.640 


18.514 


12.673 


0.127 


0.102 


0.114 


0.978 


14.866 


8.034 


1 .833 


2.549 


2.197 


2.535 


5.577 


4.081 


0.280 





0.138 


0.244 


0.532 


0.390 


0.153 


0.201 


0.177 


3.495 


6.384 


4.962 


0.113 


0.507 


0.313 


0.004 





0.002 


0.015 


0.011 


0.013 





0.004 


0.002 


0.007 


0.007 


0.007 


12.854 


13.247 


13.054 


9.225 


10.511 


9.878 


0.065 


0.085 


0.075 





0.004 


0.002 


0.131 


0.468 


0.302 


0.015 


0.222 


0.120 


0.015 


0.014 


0.014 


1 .207 


2.996 


2.116 


1 .498 


2.254 


1 .882 


0.018 


1 .454 


0.748 


0.222 


0.007 


0.115 


52.154 


165.939 


158.332 



'Area 5 
Area 7 



in Figure 12-1 
in Figure 12-1 



Sheet 2 of 2 



12-14 



Table 12-4. Five-year Average of Birds Sighted per Party-Hour 
in December for Two Areas in Alton Pool, 1973- 
1977.^ 



Number of Birds per Party-Hour 



Species 

Goshawk 

Sharp- shinned hawk 

Cooper's hawk 

Red- tailed hawk 

Red-shouldered hawk 

Rough- legged hawk 

Golden eagle 

Marsh hawk 

Peregrine falcon 

American kestrel 

Bobwhite 

Rock dove 

Mourning dove 

Screech owl 

Great-horned owl 

Barred owl 

Long-eared owl 

Saw -whet owl 

Belted kingfisher 

Common flicker 

Pileated woodpecker 

Red-bellied woodpecker 

Red-headed woodpecker 

Yellow-bellied sapsucker 

Hairy woodpecker 

Downy woodpecker 

Horned lark 

Blue jay 

Common crow 

Black-capped chickadee 

Carolina chickadee 

Tufted titmouse 

White-breasted nuthatch 

Red-breasted nuthatch 

Brown creeper 

Winter wren 

Carolina wren 

Short-billed marsh wren 

Mockingbird 

Brown thrasher 

American robin 

Wood thrush 

Hermit thrush 



Pere Marquette , 
State Park c Elsah Mean 



0.003 





0.002 


0.01 1 





0.008 


0.003 





0.002 


0.704 


0.110 


0.518 


0.003 





0.002 


0.045 





0.031 


0.003 





0.002 


0.109 


0.018 


0.081 


0.003 


0.006 


0.004 


0.358 


0.037 


0.257 


0.626 


0.460 


0.574 


0.729 


0.521 


0.664 


1 .684 


0.804 


1.409 


0.003 





0.002 


0.025 


0.037 


0.029 


0.045 


0.043 


0.044 


0.003 


0.018 


0.008 


0.003 





0.002 


0.011 


0.025 


0.015 


1 .556 


0.184 


1 .127 


0.285 


0.129 


0.236 


2.165 


1 .160 


1 .850 


2.344 


0.656 


1 .816 


0.078 


0.110 


0.088 


0.209 


0.147 


0.190 


2.184 


0.773 


1 .743 


0.475 





0.326 


2.511 


2.577 


2.532 


7.539 


0.466 


5.326 


0.332 


2.294 


2.866 


0.014 





0.010 


2.313 


1 .773 


2.144 


0.919 


0.859 


0.900 


0.006 


0.018 


0.010 


0.204 


0.012 


0.144 


0.078 


0.012 


0.058 


0.855 


0.294 


0.679 


0.003 





0.002 


0.184 


0.313 


0.225 


0.006 


0.006 


0.006 


0.802 


0.153 


0.599 


0.003 





0.002 


0.006 





0.004 



Sheet 1 of 2 



12-15 



Table 12-4 concluded -- Average Birds, Alton Pool 



Number of Birds per Party-Hour 



Species 

Varied thrush 
Eastern bluebird 
Golden-crovned kinglet 
Ruby-crowned kinglet 
Cedar waxwing 
Loggerhead shrike 
Starling 

Yellow-rumped warbler 
House sparrow 
European tree sparrow 
Eastern meadowlark 
Red-winged blackbird 
Rusty blackbird 
Brewer's blackbird 
Common grackle 
Brown-headed cowbird 
Cardinal 
Indigo bunting 
Evening grosbeak 
Purple finch 
Pine siskin 
American goldfinch 
Rufous-sided towhee 
LeConte's sparrow 
Vesper sparrow 
Dark-eyed junco 
Tree sparrow 
Chipping sparrow 
Field sparrow 
Harris ' sparrow 
White-crowned sparrow 
White- throated sparrow 
Fox sparrow 
Lincoln's sparrow 
Swamp sparrow 
Song sparrow 
Lapland longspur 

Total 



Pere Marquette^ j 
State Park Elsah Mean 










25 


23 



80 



33 
1 
4 




2 




11 
7 







2 
2 




003 
427 
405 
075 
260 
022 
377 
053 
679 
615 
997 
268 
101 
Oil 
349 
229 
827 
003 
Oil 
073 
Oil 
070 
006 
003 
008 
855 
796 

268 
003 
302 
830 
047 

430 
542 
112 








0, 


,002 


0, 


,055 


0, 


,311 


0, 


.074 


0, 


.301 


0, 


.123 


0, 


.090 


0, 


.067 


0, 


.200 







0, 


.015 


4, 


.460 


18, 


.833 







0, 


.036 


9. 


.307 


19, 


.182 


0, 


,025 


0, 


.430 


0, 


.043 


0, 


.699 


1 , 


.448 


55, 


.608 


0, 


.012 


0. 


.073 







0, 


.008 


;5, 


,533 


30, 


.904 







0, 


.845 


4, 


,153 


4, 


.616 







0, 


.002 


0, 


,055 


0, 


.025 


0. 


,080 


0, 


.075 







0, 


.008 


1 , 


,270 


1 


.820 


0, 


,055 


0, 


.021 







0, 


.002 







0, 


.006 


8, 


,613 


10, 


.841 


0, 


,245 


5, 


.434 


0, 


,043 


0, 


.013 


0. 


,037 


0, 


.196 


0, 


,018 


0, 


.008 


0, 


,245 


0, 


.284 


0, 


,442 


0, 


.708 


0, 


,074 


0, 


.056 


0. 


,049 


0, 


.015 


0. 


,061 


1 , 


.689 


0, 


.276 


1 , 


.833 







0, 


.077 



229.510 



70.878 181.803 



'Audubon Christman bird counts, 1973-1977. 

Species considered separately elsewhere in the report are 
not included in this listing. 

'"Area 8 in Figure 12-1 . 



Area 9 in Figure 12-1 



Sheet 2 of 2 



12-16 
Other Avifauna 



in this region included cardinals, black-capped chickadees, 
blue jays, tufted titmice, red-bellied woodpeckers, song 
sparrows, red-headed woodpeckers ( Melanerpes ery throcephalus ) , 
American goldfinches, downy woodpeckers, swamp sparrows, 
mourning doves, and common flickers ( Colaptes auratus ) , 
respectively (Table 12-4). 

Diversity of species varied little among the regions 
of the river. Number of species reported ranged from 71 in 
the Upper Pools (Table 12-1) of the Illinois River to 81 in 
the La Grange Pool (Table 12-3 ). The Alton Pool sup- 
ported the greatest population of wintering birds with an 
average of 181 birds sighted per party-hour (Tablel2-4). 
La Grange Pool, Peoria Pool, and the Upper Pools follow 
with 158, 132, and 102 birds sighted per party-hour of 
observation, respectively (Tables 12-5, 12-2, 12-1). Differences 
in the numbers of birds and diversity of species observed 
were generally a result of differences in habitat. 
The five-year average was used to minimize observer dif- 
ferences and unusual bird behavior. 

On 28 June 1978, Drs . Jean and Richard Graber, Illinois 
Natural History Survey, conducted a strip census of popula- 
tions of birds in the bottomland forest at Grand Island, 
Mason County (Figure 12-1, Table 12-5). Bird populations 
were generally low in 1978 (Jean Graber, personal communi- 
cation), but, in order of abundance, common grackles, red- 
headed woodpeckers, red-winged blackbirds, blue jays, star- 
lings, black-capped chickadees, downy woodpeckers, American 
robins, red-bellied woodpeckers, indigo buntings ( Passerina 
cyanea ) , northern orioles ( Icterus galbula ) , and rose- 
breasted grosbeaks ( Pheucticus ludovicianus ) were still 
fairly common (Table 12-5) . However, several summer resi- 
dents of the bottomland forest, including the house wren 
( Troglodytes aedon) , the blue-gray gnatcatcher ( Polioptila 
caerule a) , the scarlet tanager ( Piranga olivaceaj ^ the 
American redstart ( Setophaga rutici 11a ) , the yellow- 
throated warbler ( Dendroica dominica ) , the cerulean 
warbler (D. cerulea ) , and the northern parula warbler 
( Parula americana ) were surprisingly absent from the 
transect area. Blem and Blem (1975: 161) found that the 
floodplain forest hosts its greatest diversity of bird 
species between May and August and its lowest during mid- 
winter. 

Seasonal changes in species composition of forest bird 
populations are pronounced. Families such as Tyrannidae, 
Hirundinidae , Vireonidae, Parulidae, and Thraupidae are 



12-17 

Table 12-5. Census of Breeding Birds per 40.5 ha (100 a) of 

Bottomland Forest -- Grand Island (La Grange Pool), 
28 June 1978. ^ » ^ 

Species Number of Individuals per 40.5 ha (1Q0 a) 

Great blue heron 

Great egret 

Mallard 

Wood duck 

Mourning dove 

Yellow-billed cuckoo 

Common flicker 

Pileated woodpecker 

Red-bellied woodpecker 

Red-headed woodpecker 

Hairy woodpecker 

Downy woodpecker 

Great crested flycatcher 

Eastern wood pewee 

Tree swallow 

Barn swallow 

Purple martin 

Blue jay 

Common crow 

Black-capped chickadee 

Tufted titmouse 

White-breasted nuthatch 

Gray catbird 

Brown thrasher 

American robin 

Wood thrush 

Starling 

Yellow- throated vireo 

Red-eyed vireo 

Warbling vireo 

Prothonotary warbler 

Common yellowthroat 

Red-winged blackbird 

Northern oriole 

Common grackle 

Brown-headed cowbird 

Cardinal 

Rose-breasted grosbeak 

Indigo bunting 

Song sparrow 

Total 40 species 



4. 


,81 


1 . 


,60 


4. 


,81 


1 . 


.60 


6. 


.41 


4, 


.81 


8, 


.02 


1 , 


.60 


17, 


.64 


52, 


.91 


6, 


.41 


24, 


.05 


3, 


.05 


4, 


.81 
pc 


1 , 


.60, 
.62^ 


9, 


33, 


.67 


3, 


.21 


24, 


.05 


4, 


.81 


14, 


.43 


6, 


.41 


1 , 


.60 


17, 


.64 
pc 


24, 


.05 


1 , 

3, 


.60 
P^ 
.21 


6 


.41 


1 


.60 


33 


.67 


17 


.67 


262 


.95 


8 


.02 


12 


.83 


16 


.03 


17 


.64 


9 


.62 


674 


.87 



^Strip census conducted by Drs. Richard R. and Jean W. Graber 
Illinois Natural History Survey. 

Area 6 in Figure 12-1.- 

''Present but outside of transect area. 

Present because of martin houses located in Bath, Illinois. 



12-18 .| 
Other Avifauna i 



conspicuously absent in winter because of their highly- 
insectivorous diets. The species that remain in the 
project area year-round are more flexible in their food 
habits . 

Forest bird populations also undergo seasonal changes 
in numbers. No comparisons can be made based on data in this re 
port. However, Blem and Blem (1975: 161) reported that 
forest avian populations peak twice each year. One peak 
occurs about the end of July after nesting is completed 
and the other occurs between November and February when 
winter residents attain their maximum population densities. 
The lowest point in annual bird numbers occurs in September 
when summer residents are gone and winter residents have 
not yet arrived. Overall the biomass of birds in the 
floodplain is consistently greater than in the upland 
forest (Blem and Blem, 1975: 163). This emphasizes the 
importance of the Illinois River bottomland habitats to 
the numerous species of birds. 

EFFECTS OF INCREASED DIVERSION 



The effects of an increased diversion of water into the 
Illinois River on such a diverse group of avifauna are dif- 
ficult to prognosticate . The problem can best be approached 
by first considering the probable direct effects of the 
proposed diversion on residents from the habitat viewpoint, 
and then considering the indirect effects from the stand- 
point of food availability. 

Changing water levels would have the greatest impact 
on the marsh community. Initially, flooding of nests would 
be detrimental to marsh birds. Subsequently, a decrease in 
abundance of marsh habitat may result from increased water 
levels and would probably have negative effects on popula- 
tions of marsh birds. This occurred during the original 
diversion (Gates, 1911: 7). According to Weller and 
Spatcher (1965: 28), avian production reaches its peak in 
semi-permanent marshes when the emergent- cover- to-water 
ratio is 50:50 with good interspersion . Johnsgard (1956: 
700) believes that the net results of all ecological changes 
resulting from water fluctuations would be a decrease in 
variety of marsh flora and fauna with concurrent increases 
in the more adaptable species. 



12-19 
Other Avifauna 



In the bottomland forest habitat, ground-nesting and 
shrub-nesting avian species, which Fawver (1947: 185) 
found to comprise 1.3 and 47.2'o, respectively, of the 
typical forest breeding population, would be the only 
birds subject to direct nest destruction as a result of 
high water. Die-offs of hydrophytic willow and buttonbush 
thickets, like those which occurred following the initial 
1900 diversion (Gates, 1911: 15), would probably have more 
permanent detrimental effects on shrub-nesting birds. 
Death of bottomland trees that could result from prolonged 
periods of inundation may be beneficial to cavity-nesting 
birds which were found to make up about one-third of the 
avian breeding population (Fawver, 1947: 185). Highly 
suitable nesting conditions provided by dead trees resul- 
ted in an increased woodpecker population at Calhoun 
Point State Conservation Area, Calhoun County, 1 year after 
flooding (Yeager, 1949: 62). Conversely, tree death would 
probably be detrimental to canopy-nesting species that 
prefer living trees. The abundance of winter cover that 
would be affected by flooding and the resulting impact on 
overwintering bird populations are difficult to predict. 

Enhanced water flow could have both positive and 
negative effects on food availability. It could provide 
more areas of open water in winter for feeding raptors 
and kingfishers by retarding ice formation. However, if 
increased diversion results in more turbidity, then the 
capture of food by these s ight- feeding species may be im- 
paired. Populations of macrobenthos food sources vary with 
water depth, water stability, and abundance of submerged 
aquatic plants that serve as growth substrates (Boyer 
and Psujek, 1977: 338). The possible effects of an 
increased diversion on production of macrobenthos are complex; 
consequently, no conclusions about the indirect effects on 
birds can be made. In the terrestrial habitat, inverteb- 
rates may be benefited if the moisture content of the 
forest floor increases but is not flooded (Shelford, 1954: 
136). Theories differ about the effects of inundation on 
small mammal populations in the floodplain forest. Some 
investigators believe that flooding has little or no ef- 
fect (Ruffer, 1961: 494) whereas great reductions in popu- 
lations as a result of flooding have been observed (Blair, 
1939: 305). Cumulative effects of inundation on the 
seed-, fruit-, and nut-bearing plants that small birds 
depend upon especially in winter, are difficult to evalu- 
ate, but prolonged inundation would be detrimental. 



13-1 



CHAPTER 13 : MAMMALS 



Mammals are an important natural resource of the Illinois 
River valley. Consumptive uses that remove a portion of this 
resource and can be evaluated monetarily include hunting and 
trapping. The value of mammals for nonconsumptive uses such 
as observation, wildlife photography, and canid-chasing cannot 
be clearly quantified economically, but demand for these types 
of recreation is increasing. Mammals are also an important 
ecological constituent in the communities of the Illinois 
River valley. 



NATURAL HISTORY 



Forty-nine species of mammals from 15 families may 
occur in the project area (see Table C-10in Appendix C for 
distribution and abundance), but most of these species are 
observed infrequently because of their nocturnal, crepuscu- 
lar, or secretive habits. The diversity of physical adapta- 
tions and habitat requirements exhibited by these mammals 
necessitates a discussion at the order or family level of 
taxonomic classification. 



Order Marsupialif 

The opossum (Family Didelphidae, Didelphi s marsupialis ) 
is a woodland inhabitant that makes its home in hollow trees 
or burrows. Small birds and mammals, fruits, insects, and 
carrion are the primary foods of this slow, solitary animal 
(Hoffmeister and Mohr, 1972: 47, 48). Dense populations of 
opossums have been observed in bottomland forests (Yeager and 
Anderson, 1944: 170) but their poor swimming ability and 
inefficiency in securing food from water make them ill- 
adapted for high water conditions (Yeager, 1949: 60). 

Order Insectivora 

Shrews and moles tunnel in the soil of forests, edge 
communities, swampy and brushy habitats, and grassy open 
areas for food items such as insects, snails, and earthworms. 



13-2 
Mamma Is 



Because their insect diet often includes species injurious 
to crops, these insectivores are beneficial to man. Young are 
raised in underground cavities or in nests under logs 
(Hoffmeister and Mohr, 1972: 50, 52, 56, 60). 

Order Chiroptera 

Bats found in the Illinois River valley (Family Vesper- 
tilionidae) can be divided into 2 groups according to their 
habits: (1) solitary species that roost in trees and are 
migratory, and (2) gregarious species that roost in caves or 
buildings and do not migrate (Hoffmeister and Mohr, 1972: 
64). All of the species are nocturnal insect-feeders and are, 
therefore, helpful in reducing numbers of insect pests 
(Burt and Grossenheider , 1952: 22). Backwater areas that 
serve as breeding grounds for many types of insects are 
attractive to bats. 



Order Lagomorpha 

Although eastern cottontails (Family Leporidae, Sy Ivi - 
lagus f loridanus ) are found in almost every terrestrial 
habitat, they are especially attracted to dry bottomlands 
and edge situations. High or inland sites are preferred 
by the rabbits for construction of their shallow ground 
nests because of greater safety from flooding. Grasses, 
legumes, and broad-leaved weeds comprise the bulk of the 
cottontail's diet, but buds, bark, and twigs of shrubs and 
small trees may be consumed in winter (Hoffmeister and 
Mohr, 1972: 194, 195). Cottontails are the most heavily 
hunted of all the small game species in Illinois. 



Order Rodentia 

Seven members of the squirrel family (Family Sciuridae) 
reside in the Illinois Valley. Because ground squirrels 
(S permophi lus tridecemlineatus and S. f ranklinii ) are 
inhabitants of grassy pastures and old fields, they probably 
occur only occasionally in the project area. Eastern chip- 
munks ( Tamias striatus ) are associated with brushy woods 
and wooded bluffs where they use old logs and stones for 
shelter and nests. Forest edges provide sites for the 
ground dens of woodchucks ( Marmota monax) . The Southern 
flying squirrel ( Glaucomvs volans ) , the only nocturnal 
squirrel species, uses tree cavities in heavily wooded areas 
for nesting (Hoffmeister and Mohr, 1972: 131, 140, 149). 
Fox and gray squirrels ( Sciurus niger and S. carol inens is ) 



13-3 
Mammals 



are undoubtedly the best-known sciurids of the bottomland 
forest as a result of their high visibility and great hunting 
value as small game species. Both gray and fox squirrels 
raise their young in leaf nests or tree hollows (Hoffmeister 
and Mohr, 1972: 144, 147). The gray squirrel prefers extensive 
tracts of forest (Nixon et al., 1978b:3), whereas the fox 
squirrel is more adaptable and occurs in a variety of habitats. 
Shelford (1954: 136) observed that gray and fox squirrels 
were present throughout the bottomland forest including 
the Cottonwood community but noted that they were more abundant 
in the older stages. When mast trees are present in the 
bottomland, squirrel abundance can average 2.5 squirrels 
per hectare (1 squirrel per acre). In stands of strictly 
Cottonwood and silver maple, abundance decreases to approxi- 
mately 1 squirrel per 2 hectares (1 squirrel per 3 to 6 
acres). Seeds, grain, mast, and insects are staple foods 
for all of the sciurid species except woodchucks which feed 
on legumes and greens (Hoffmeister and Mohr, 1972: 131). 
The family Sciuridae with its wide variety of arboreal and 
terrestrial species is an important family economically 
inasmuch as 3 members (woodchucks and gray and fox squirrels) 
re small game species prized by hunters. 



w 



a 

Habitat preferences of mice and voles (Family Criceti- 
dae) vary from wet meadows to woodlands. Nest sites differ 
among species and can be constructed below ground, on the 
ground beneath logs and debris, or above the ground in stumps 
and old bird nests (Hoffmeister and Mohr, 1972: 157, 159, 
172). Seeds are the major foods of most species of mice and 
voles but arthropods, mast, and leaves of dicot plants are 
also consumed during some seasons of the year. Even though 
the floodplain habitats are harsher and more unstable than 
the upland habitats, recruitment of young is higher in the 
floodplain (Batzli, 1977: 26). 

Muskrats ( Ondatra zibethicus ) , the largest and most im- 
portant members of the Family Cricetidae, are closely asso- 
ciated with the Illinois River and its backwaters. Depending 
on the available habitat, muskrats either build lodges in 
the shallow water of marshes or excavate dens in mud banks 
to raise their young. Bank dens have become the more pre- 
valent type as a result of increased destruction of marsh 
habitat. Although the fur of these animals is valued by 
trappers, such denning activities in earthen dams and levees 
are often very destructive. The nutritional needs of these 
aquatic mammals are satisfied by roots, tubers, and green 
vegetation (Hoffmeister and Mohr, 1972: 179, 181). Bul- 
rushes, marsh smartweed, black willow, and duck potato are 
plants favored by muskrats in the Illinois Valley (Bellrose, 



13-4 
Mammals 



1950: 314). Stable water levels are preferred by muskrats 
(Bellrose and Brown, 1941: 206). 

Another aquatic furbearer that is becoming increasingly- 
abundant in the Illinois Valley after near-extirnation 
in the early 1900's is the beaver (Family Castoridae, Castor ' 
canadensis ) . Aquatic plants and poplar, maple, birch, and 
willow trees growing near a continuous supply of water are 
major food items for these rodents. Beavers, like muskrats, 
may either excavate bank dens or build lodges but, in addi- 
tion, they construct dams of tree branches, sticks, stones, 
and mud (Hoffmeister and Mohr, 1972: 154-155). When these 
dams interfere with waterways used by man, the beaver can 
be somewhat of a pest. 

Order Carnivora 

Coyotes ( Canis latrans ) and red and gray foxes CFaniily 
Canidae, Vulpes fulva , Urocyon cinereoargenteus ) have recently 
become three of the most valuable furbearing species in the 
project area. Gray foxes are restricted to forest and river 
bottom habitats where they den in hollow trees or rock out- 
croppings (Hoffmeister and Mohr, 1972: 115). The more 
versatile and adaptable coyotes and red foxes are able to 
live in interspersed agricultural lands. Both of these 
species modify the abandoned burrows of woodchucks for their 
dens. Rabbits, rodents, birds, insects, fruits, and vege- 
table matter are the major food items of canids (Hoffmeister 
and Mohr, 1972: 113, 116, 118) . 

The raccoon (Family Procyonidae, Procyon lotor ) , con- 
sidered to be the best furbearer for income, sport, and 
aesthetic appeal (Brown and Yeager, 1943: 463), is very 
abundant in wooded river bottoms of the Illinois Valley. 
Dry tree cavities are the typical den sites for raccoons, 
but ground cavities may be used. Raccoons are versatile, 
opportunistic feeders that forage along streams for such 
food items as fruits, grains, invertebrates, birds, rep- 
tiles, and mammals (Hoffmeister and Mohr, 1972: 94). Be- 
sides their economic value, raccoons provide substantial 
recreational value for hunters and trappers. 

The family Mustelidae encompasses a collection of 
species with a spectrum of lifestyles ranging from semi- 
aquatic to strictly terrestrial. The river otter ( Lutra 
canadensis ) . a threatened species that is a relatively rare 
and highly aquatic inhabitant of streams and lakes, occurs 
sporadically in several Illinois counties (Hoffmeister and 



Mammals 



13-5 



Mohr, 197 
the proje 
equally a 
high wate 
(Yeager, 
tebrates , 
(Hof fmeis 
many mink 
h o 1 1 ow t r 
fencerows 
( Mus tela 
feed oppo 
birds, bu 
and small 
ferred by 
area (Hof 
for groun 
mus telids 



2: 105 
ct are 
t home 
r in t 
1949: 

and f 
ter an 
s live 
ees (B 

provi 
spp.) 
r tunis 
t we as 

mamma 

badge 
fmeis t 
d dens 



). It 
a . The 

on Ian 
he floo 
60) . M 
ish com. 
d Mohr, 

on or 
rown an 
de habi 
and str 
tically 
els con 
Is. Th 
rs ( Tax 
er and 

are a 



is unl 

mink 
d and 
dplain 
uskrat 
prise 
1972: 
near w 
d Yeag 
tat fo 
iped s 
on ca 
centra 
e sand 
idea t 



ikely 

(Must 



tha 
ela 



in th 

than 

s , bi 

the b 

102) 

ooded 

er , 1 

r the 

kunks 

rrion 

te mo 

prai 

axus) 



Mohr, 
necess 



1972: 
ary h 



e wa 
any 

rds , 

ulk 

. A 
isl 

943: 
mor 
(Me 

, in 

re s 

ries 
lie 
100 

abit 



t river o 

vison ) , b 

ter , is 1 

other fu 

repti les 

of the mi 

long the 

ands wher 

475). B 

e terrest 

phit is me 

sects , sm 

pecif ical 

and open 

outs ide 

-110) . H 

at requir 



tters ex 
ecause i 
ess affe 
rbearing 
, aquati 
nk ' s die 
1 1 linois 
e they d 
rushy ar 
rial wea 
phi t is ) . 
all mamm 
ly on ro 
country 
of the p 
igh and 
ement of 



IS t m 
t is 
cted by 

species 
c inver- 
t 

River , 
en in 
eas and 
sels 

Skunks 
als , or 
dents 

pre- 
roject 
dry areas 

all 



Bobcats (Family Felidae, Lvnx rufus ) , now threatened and 
rare in Illinois, may occur in neavily wooded bottomlands in 
the southern portion of the river valley. Bobcats den in 
hollow trees or logs and feed on small mammals, birds, and 
insects (Hoffmeister and Mohr, 1972: 121, 122). 



Order Artiodactyla 



The 
tailed d 
indicate 
among th 
of deer 
C-62). 
deer whi 
as well 
202, 204 
s om e t i m e 
as well, 
to swim 
Illinois 



impor 
eer (F 
d by t 
e firs 
to the 
Open w 
ch fee 
as agr 
) . Ma 
s feed 
This 
the II 

N a t u r 



tance 
amily 
he fa 
t to 

Stat 
oods 
d on 
icult 
rtin 
exte 
spec 
1 inoi 
al Hi 



of 

Cer 
ct t 
reop 
e in 
and 
a va 
ural 
and 
nsiv 
ies 
s Ri 
stor 



the I 
vidae 
hat s 
en fo 

the 
thick 
riety 

crop 
Uhler 
ely o 
is hi 
ver r 
y Sur 



llino 
, Odo 



is R i v 
coi leu 



ome c 
r hun 
1930' 
ets a 

of w 
s (Ho 

(193 
n mar 
ghly 
ather 
vey , 



ount le 
ting a 
s (Bel 
re the 
oody a 
f fmeis 
9: 139 
sh and 
mobi le 
readi 
person 



er bottoms to white- 
s' vi rginianus ) is 
s along the river were 
fter the reintroduction 
Irose et al. , 1977: 

primary habitats of 
nd herbaceous plants 
ter and Mohr, 1972: 
) reported that deer 
aquatic vegetation 
and has been known 
ly (Robert Crompton, 
al communication). 



Interest in the white-tailed deer as Illinois' only big- 
game animal has increased in accordance with its population 
during recent years. Deer have substantial economical and 
recreational value in Illinois. 



13-6 1 
Mammals I 

j 
MAMMALS OF RECREATIONAL AND ECONOMIC IMPORTANCE ' 

1 
i 
In addition to their tangible value for food and income, ; 
the 14 species of game and furbearing mammals harvested by 
Illinois hunters and trappers have intangible value for sport ] 
and recreation. Harvest data for these mammals were avail- j 
able only on a county basis and, in some cases, only on ' i 
the statewide level. Considering the intensity of farming 
in most of the 23 project area counties, some of the best 
wildlife habitat is located along the river. 

Small Game Mammals 

Cottontails, gray and fox squirrels, woodchucks , rac- 
coons, and red and gray foxes comprise the small game species. 
Rabbits and squirrels are the most important of these species 
probably because of their palatability and widespread occur- 
rence. Although raccoons and foxes provide sport for hunters, 
they are primarily harvested for their fur by trappers and 
will be discussed in conjunction with the remainder of the 
furbearers. Woodchucks are of minor importance to hunters 
and do not merit separate discussion. 

Cott ontai Is 

According to Preno and Labisky (1971: 43), more resi- 
dent hunters have hunted rabbits in recent years than any 
other small game species. During the period of their study 
(1956-1969), an average of 334,000 hunters bagged 3,810,900 
rabbits annually, which is approximately 11 rabbits per 
hunter in a season (Preno and Labisky, 1971: 43, 46). Be- 
cause of declining rabbit abundance, hunter interest has 
been waning statewide during the 1970's. The decline is prirarih 
result of habitat loss from intensive farming practices and 
increased acreages of corn and soybeans. 

Based on the 1956-1969 data of Preno and Labisky 
(1971: 71-76), an average of 24.21. of the state harvest of 
cottontails was bagged in the project area counties (Tablel3-1 ). 
The largest portion (12.61.) of the kill in the project area 
was harvested in Madison County (Alton Pool) where an average 
of 610 rabbits were bagged per 1,000 ha (247 per 1,000 acres) 
(Preno and Labisky, 1971: 48). Tazewell, Peoria, and Fulton 
counties (La Grange and Peoria pools) were also high in the 
rabbit harvest claiming 7.9, 7.3, and 7.11 of the project 
area kill, respectively. 



13-7 



Table 13-1. Annual Cottontail Values of the Mean Number and 
Percentage Harvested and Hunter-trips Expended 
and the Mean Kill Per Hunter-trip in the Project 
Area Counties, 1956-1969. ^ 





Mean 


Number 


% of 


Mean 


Number 


% of 


Mean Kill 




Harvested 


Total 


Hunter' 


-Trips 


Total 


per 




Annually 


Har- 


Annually 


Hunter- 


Hunter- 


County 


(in 


100's) 


vested 


(in 


100's) 


trips 


trip 


Cook 




414 


4.5 




365 


6.9 


1 .1 


Du Page 




297 


3.2 




290 


5.5 


1 .0 


Will 




536 


5.8 




479 


9.0 


1.1 


Grundy 




234 


2.6 




190 


3.6 


1 .2 


La Salle 




637 


6.9 




477 


9.0 


1.3 


Bureau 




450 


4.9 




236 


4.4 


1 .9 


Putnam 




120 


1 .3 




70 


1 .3 


1 .7 


Marshall 




232 


2.5 




130 


2.5 


1 .8 


Woodford 




337 


3.7 




218 


4.1 


1 .6 


Peoria 




667 


7.3 




353 


6.7 


1 .9 


Tazewell 




728 


7.9 




423 


8.0 


1 .7 


Fulton 




647 


7.1 




293 


5.5 


2.2 


Mason 




267 


2.9 




145 


2.7 


1 .8 


Schuyler 




148 


1.6 




73 


1 .4 


2.0 


Cass 




217 


2.4 




120 


2.3 


1 .8 


Brown 




146 


1.6 




65 


1 .2 


2.2 


Morgan 




344 


3.7 




148 


2.8 


2.3 


Scott 




167 


1.8 




73 


1 .4 


2.3 


Pike 




623 


6.8 




222 


4.2 


2.8 


Greene 




435 


4.7 




181 


3.4 


2.4 


Calhoun 




105 


1.1 




50 


1 .0 


2.1 


Jersey 




267 


2.9 




130 


2.5 


2.1 


Madison 


1 


,158 


12.6 




573 


10.8 


2.0 


Total 


9 


,176 


99.8 


5 


,304 


100.2 




Mean 














1 .8 



Data taken from Preno and Labisky, 1971: 48, 71-76 



13-8 

Mammals 

Hunting pressure is another factor that should be 
considered in an evaluation of cottontail harvest. Project 
area counties received an average of 26. Al of the statewide 
hunting pressure (expressed as hunter- trips) (Table 13-1). 
Madison, Will, La Salle, and Tazewell counties were the 
most heavily hunted counties in the project area with 10.8, 
9.0, 9.0, and S.O^o of the total hunter- trips , respectively. 

Hunting success was greatest in Pike County where 
hunters bagged an average of 2.8 rabbits per trip (Table13-1). 
Greene, Morgan, and Scott counties followed with 2.4, 2.3, 
and 2.3 rabbits killed per hunter-trip, respectively. 
Preno and Labisky (1971: 46) found that kill per hunter- 
trip was directly correlated with annual indices of abundance. 
Therefore, rabbits are generally more abundant in the lower 
counties of the project area than in the upper counties 
(Table 15-1 ) . 

Fox and Gray Squirrels 

Nixon et al. (1978a: 9) revealed that the average 
squirrel harvest in Illinois numbered 2,738,000 between 
1956 and 1973. An annual average of 219,167 hunters harvested 
a mean seasonal bag of 12.5 squirrels per hunter (Nixon 
et al. , 1978a: 9) . 

On the average, hunters in the project area counties 
annually bagged 24.81, of the 1956-1969 state harvest of 
squirrels (Table 13-2) . The largest portion (lO.I'O of the 
project area kill was harvested in Fulton County. Peoria, 
Pike, and Madison counties also claimed high percentages 
of the kill (8.8, 8.0, and 8.0^o, respectively). Fox 
squirrels, ubiquitous in Illinois, comprised more than 
two-thirds of the harvest in all of the project area coun- 
ties with the exceptions of Calhoun, Jersey, Pike, and 
Brown counties where gray squirrels accounted for 51, 44, 
37, and 35°<, of the kill, respectively (Nixon et al., 1978b: 
24). The smaller proportion of gray squirrels in the 
harvest resulted from their restricted distribution governed 
by their requirement for heavily forested habitat and partly 
from their elusiveness. 

Squirrel hunters averaged more hunting trips per season 
between 1956 and 1969 than hunters of any other small game 
species (Preno and Labisky, 1971: 36). Hunting pressure in 
the proiect area was heaviest in Peoria, Fulton, and Madison 
counties (Table13-2 ) . 

Based on mean kill per hunter-trip, hunting success was 
greatest in Pike and Calhoun counties (Table 13-2). Hunters 



13-9 



Table 13-2. Annual Gray and Fox Squirrel Values of the Mean 
Number and Percentage Harvested and Hunter-trips 
Expended and the Mean Kill Per Hunter-trip in the 
Project Area Counties, 1956-1969.^ 



County 


Mean Number 
Harvested 
Annual Iv 
(in 100''s) 


% of 
Total 
Har- 
vested 


Mean Number 
Hunter- trips 
Annually 
(in 100''s) 


% of 
Total 
Hunter- 
trips 


Mean Kill 
per 

Hunter- 
trip 


Cook 




114 


1 .7 




88 


2.5 


1 .4 


Du Page 




96 


1 .4 




68 


1 .9 


1 .4 


Will 




154 


2.3 




124 


3.5 


1 .3 


Grundy 




148 


2.2 




109 


3.1 


1 .4 


La Salle 




331 


4.9 




230 


6.5 


1 .5 


Bureau 




312 


4.6 




187 


5.3 


1 .6 


Putnam 




96 


1 .4 




53 


1 .5 


1 .8 


Marshall 




198 


2.9 




108 


3.0 


1 .8 


Woodford 




237 


3.5 




143 


4.0 


1 .6 


Peoria 




600 


8.8 




330 


9.3 


1 .8 


Tazewell 




463 


6.8 




263 


7.4 


1 .8 


Fulton 




687 


10.1 




307 


8.7 


2.2 


Mason 




359 


5.3 




169 


4.8 


2.1 


Schuyler 




235 


3.4 




101 


2.8 


2.3 


Cass 




230 


3.4 




106 


3.0 


2.2 


Brown 




180 


2.6 




74 


2.1 


2.4 


Morgan 




172 


2.5 




79 


2.2 


2.2 


Scott 




143 


2.1 




64 


1 .8 


2.2 


Pike 




545 


8.0 




221 


6.2 


2.5 


Greene 




355 


5.2 




151 


4.3 


2.4 


Calhoun 




323 


4.7 




128 


3.6 


2.5 


Jersey 




297 


4.4 




136 


3.8 


2.2 


Madison 




545 


8.0 




305 


8.6 


1 .8 


Total 

Mean 


6 


,820 


100.2 


3 


,544 


99.9 


1 .9 



Data taken from Preno and Labisky, 1971: 40, 71-76. 



13-10 



Mammals 



in these counties bagged an average of 2.5 squirrels per trip, 
Success was greater, overall, in the southernmost portion of 
the project area and decreased progressively northward. 

White-tailed Deer 



The white-tailed deer is the only big-game animal re- 
maining in Illinois. Interest in hunting this species has 
been increasing almost as fast as the population since the 
hunting season reopened in 1957 . Besides providing sport 
for archers and gunners, deer yield large quantities of 
palatable meat. 

A total of 3,473 deer, 21.41. of the state total, were 
harvested in the project area counties during the 1977 
hunting season (Table 13-3). Almost one-fifth of the deer 
harvested in the project area during the 1974-1977 seasons 
were taken in Pike County. Hunters in Brown, Schuyler, 
and Bureau counties consistently harvested large numbers as 
well . 



tly more than 16,000 hunters (21.4^o of the state 
ted deer in the project area. Pike, Bureau, and 
ties received the heaviest hunting pressure -- 

and 7.6o of the project area total, respectively 
). Since 1974, hunters have enjoyed the greatest 
Pike, Schuyler, and Brown counties where a deer 

for every 3 or 4 hunters. For the entire project 
t one-tenth of the hunters were successful in 
deer and success did not differ noticeably be- 
southern and northern regions. 



Sligh 


total) 


hun 


Brown 


coun 


11 .6, 


8.1 , 


(Table 


13-3 


success in 


was ki 


lied 


area. 


abou 


bagging a 


tween 


the 



Furbearers 

Illinois consistently ranks among the top 10 states in 
the nation for total pelt harvest (Hubert, 1979: 3). The 
state's furbearing species include raccoons, muskrats, red 
and gray foxes, opossums, minks, beavers, skunks, weasels, 
and coyotes. Muskrats, minks, weasels, and beavers can 
legally be taken in traps only whereas the other species can 
be harvested by hunting or trapping. The recreational im- 
portance of furbearers is documented by Hubert (1979: 8) 
who found that 10.51, of all hunter-days during the 1976-77 
season were devoted to fur species as compared to 9.51> for 
waterfowl and 7.71, for doves. 



13-11 



Table 13-5. Deer Harvest and Hunter Success in the Project 
Area Counties, 1977. ^ 





Number of 




Number 




Hunters 




Deer 


% of 




of 


% of 


Per Deer 


County 


Harvested 


Total 


Hunters 


Total 


Killed 


Cook^ 


_ 


_ 




_ 


_ 


_ 


Du Page 


- 


- 




- 


- 


- 


Will 


24 


0.7 




216 


1 .3 


9.0 


Grundy 


78 


2.2 




359 


2.2 


4.6 


La Salle 


156 


4.5 




780 


4.8 


5.0 


Bureau 


202 


5.8 


1 


,313 


8.1 


6.5 


Putnam 


96 


2.8 




576 


3.5 


6.0 


Marshall 


176 


5.1 




986 


6.1 


5.6 


Woodford 


122 


3.5 




610 


3.8 


5.0 


Peoria 


163 


4.7 




750 


4.6 


4.6 


Tazewell 


89 


2.6 




481 


3.0 


5.4 


Fulton 


260 


7.5 


1 


,170 


7.2 


4.5 


Mason 


11 1 


3.2 




644 


4.0 


5.8 


Schuyler 


322 


9.3 


1 


,192 


7.3 


3.7 


Cass (+ Site M) 115 


3.3 




851 


5.2 


7.4 


Brown 


343 


9.9 


1 


,235 


7.6 


3.6 


Morgan 


89 


2.6 




481 


3.0 


5.4 


Scott 


100 


2.9 




480 


3.0 


4.8 


Pike 


647 


18.6 


1 


,877 


11.6 


2.9 


Greene 


121 


3.5 




630 


3.9 


5.2 


Calhoun 


188 


5.4 




884 


5.4 


4.7 


Jersey 


26 


0.7 




468 


2.9 


18.0 


Madison 


45 


1 .3 




266 


1 .6 


5.9 


Total 


3,473 


100.1 


16 


,249 


100.1 




Mean 


165 






774 




9.5 



a 
'No season in 1977 



Data provided by Forrest Loomis, Illinois Department of Conservatio 
b, 



13-12 
Mammals 

Harvest 

County harvest estimates for furbearers are not available 
(George Hubert, personal communication). Statewide, the es- 
timated fur harvest for the 1976-77 season was 520,000 pelts 
(Hubert, 1977a: 1). The 1977-78 harvest increased to 
627,300 pelts (Hubert, 1978a: 1), During both seasons, 
muskrats accounted for approximately one-half of the harvest 
and raccoons made up an additional one-third. Moderate 
numbers of opossums and minks were taken followed by red 
foxes, gray foxes, and coyotes. Species of minor importance 
included beaver, striped skunks, and weasels. 

The harvest of fur species is dependent upon the mar- 
ket value of pelts, weather during the hunting and trapping 
seasons, regulations, harvest pressure, and population 
numbers for the species. Decreased populations of muskrats 
and minks resulting from extensive losses of wetland habi- 
tat have probably been responsible for the marked decline in 
their harvest over the past few years. However, an average 
of 250 muskrats was harvested per 100 km (62 miles ) in 
Cass, Mason, and Tazewell counties (Hubert, 1979: 2, 24). 
Sky-rocketing harvests of raccoons have been enhanced by 
the high market demand for long-haired pelts, increased 
pelt prices, and high population numbers. Harvest of rac- 
coons in Cass, Mason, and Tazewell counties averaged 
48 animals per 100 km^ (62 miles^) (Hubert, 1979: 2, 25). 
The red fox harvest has remained relatively stable whereas 
the take of gray foxes has increased in response to the high 
market demand. Coyotes and beavers have recently become 
more important in the fur harvest because of higher demand 
and increasing populations (Hubert, 1979: 3). 

About one-fifth of the trapping licenses sold in the 
state during the 1974-75 and 1975-76 seasons were purchased 
by residents of project area counties (Table 13-4 ). Heaviest 
sales during both seasons were reported in La Salle, Ful- 
ton, and Pike counties. According to Hubert (1977b: 8, 9), 
the average seasonal take of an effective trapper during the 
1976-77 season was 30 muskrats, 3 minks, 3 beavers, 7 rac- 
coons, 5 opossums, 3 red foxes, 2 gray foxes, 3 coyotes, 
and 1 weasel. Mohr (1943: 512) believed that the size of 
the average catch per fur-taker is generally correlated 
with the size of the population. 

Fur Value 

The total sale value of furbearer pelts in the state 
amounted to $5,180,000 for the 1976-77 season and a record 
high of $6,960,000 for the 1977-78 season (Hubert, 1977a: 7; 



13-13 



Table 13-4. Resident Trapping License Sales for the Project 
Area Counties, 1974 and 1975.^ 



County 

Cook 

Du Page 

Will 

Grundy 

La Salle 

Bureau 

Putnam 

Marshall 

Woodford 

Peoria 

Tazewell 

Fulton 

Mason 

Schuyler 

Cass 

B r own 

Morgan 

Scott 

Pike 

Greene 

Calhoun 

Jersey 

Madison 



1974 1975 



Number of 


% of 


Licenses 


Total 


123 


4.5 


92 


3.4 


173 


6.3 


88 


3.2 


292 


10.7 


222 


8.1 


20 


0.7 


61 


2.2 


104 


3.8 


232 


8.5 


175 


6.4 


272 


10.0 


108 


4.0 


58 


2.1 


93 


3.4 


98 


3.6 


50 


1.8 


255 


9.4 


127 


4.7 


23 


0.8 


60 


2.2 



Number of 


% of 


Licenses 


Total 


125 


4.3 


100 


3.4 


189 


6.4 


138 


4.7 


329 


11 .2 


245 


8.3 


21 


0.7 


66 


2.2 


139 


4.7 


215 


7.3 


175 


6.0 


300 


10.2 


99 


3.4 


43 


1 .5 


131 


4.5 


78 


2.7 


55 


1.9 


260 


8.9 


137 


4.7 


38 


1 .3 


52 


1 .8 



Total 2,726 99.8 2,935 100.1 



^Data provided by George Hubert, Jr., Furbearer Biologist, 
Illinois Department of Conservation. 

^No data. 



13-14 



Mammals 

1978a: 12). Raccoons accounted for about 621. of the total 
value during both seasons. Muskrats, red foxes, and gray 
foxes were next in importance representing approximately 
22, 6, and 41 of the total pelt value. Red fox pelts 
brought the highest average price per pelt during 
1975-78, ranging from $34 to $47 (Table13-5). The market 
value of all furhcarcr pelts has increased appreciably 
since 1975. 



EFFECTS OF AN INCREASED DIVERSION 



The effects on mammals of an increased diversion of 
water into the Illinois River would vary. The mammals can 
be grouped into the following 4 categories for discussion 
of possible effects: semi-aquatic species, somewhat 
tolerant terrestrial species, intolerant terrestrial 
species, and arboreal species. 

Beavers, muskrats, and otters comprise the semi-aquatic 
species. Initially, an increased diversion could flood 
dens causing the death of young (Brenner, 1964: 745; Hoff- 
meister and Mohr, 1972: 380), inundate and kill stands of 
vegetation and small trees used for food, and drive the 
animals from the safety of their dens and home ranges (Bell- 
rose and Low, 1943: 177). Eventually, these detrimental 
effects may be overshadowed by the beneficial effects of 
increased water area. Yeager (1949: 57, 59) found that 
muskrats were the mammals most receptive to conditions 
brought about by flooding and would move into flooded areas 
quickly. Because otters are rare or nonexistent in the 
project area, they would be virtually unaffected. 

Terrestrial mammals such as minks, raccoons, deer, and 
selected species of mice are relatively tolerant of limited 
flooded conditions. Deer move in and out of areas freely 
with changes in water levels (Shelford, 1954: 139). Rac- 
coons, minks, and mice are able to move through the trees 
(Hoslett, 1961: 261), and all of these mammals are known 
to swim (Ruffer, 1961: 501; Yeager and Anderson, 1944: 170; 
Yeager and Rennels, 1943: 52). The presence of large old 
trees and tall stumps with cavities for dens is necessary 
for small mammals during flooding (Wetzel, 1958: 269). 
Prolonged flooding resulting in loss of habitat from the 
death of trees and other plants would be detrimental to 
these species. Food would probably be plentiful for minks 
which feed on fish, crayfish, and muskrats. However, pro- 
longed inundation could kill browse and seed- and fruit- 
producing plants that provide food for deer, mice, and 
raccoons . 



13-15 



Table 13-5. Estimated Average Prices Paid for Furbearer Pelts 
in Illinois, 1976-1978.^ 



Species 
Muskrat 



1975-76 



Seasons 



1976-77 



1977-78 



Mean 



$2.90 $ 4.44 $5.10 $4.15 



Mink 



6.00 



13.95 



13.20 



11 .05 



Raccoon 


14.00 


17.17 


18.00 


16.39 


Opossum 


1 .10 


1 .21 


2.05 


1 .45 


Red fox 


34.00 


45.61 


47.45 


42.35 


Gray fox 


16.00 


27.67 


31 .05 


24.91 


Beaver 


4.50 


7.00 


6.60 


6.03 


Striped skunk 


1 .00 


2.25 


2.20 


1 .82 


Weasel 


0.50 


0.54 


0.60 


0.55 


Coyote 


8.00 


16.07 


16.75 


13.61 



^Data taken from Hubert, G.E., Jr., 1976-77 and 1977-78 Fur 
harvest survey, Illinois Department of Conservation. 



13-16 

Mammals 



Many species of mammals found in the project area would 
be intolerant of conditions produced by prolonged high water 
and are expected to either be extirpated in the newly inunda- 
ted areas or be forced to emigrate , Blair (1939: 306) be- 
lieved that wholly terrestrial species of small mammals 
(e.g., voles, insectivores) confined to floodplain associ- 
ations would be virtually exterminated in parts of their 
ranges by flooding. During inundation, the forest floor 
is unavailable to them for foraging and nesting. After 
inundation, heavy silt deposits appear to limit any 
reinvasion particularly of the fossorial types (Terpening 
et al., 1975: 89). Yeager (1949: 61) found that foxes 
and rabbits are evicted from flooded areas as the habitat 
is reduced. Interspecific pressure for suitable ground 
dens probably resulted in the eviction of more woodchucks 
than any other species (Yeager and Anderson, 1944: 167). 
Mortality resulting from exposure was found to be very 
high among evicted woodchucks. Shelford (1954: 139) noted 
that skunks and opossums cannot live in flooded areas and 
will move in and out only to minor degrees. Initially 
but only briefly, intolerant mammals from inundated areas 
could increase the density in the remainder of the flood- 
plain before the populations re-stabilized at the carrying 
capacity of the habitat. Ultimately, a smaller area of 
suitable habitat would remain to support the mammals forced 
to emigrate because cultivated fields generally border the 
project area. Therefore, the numbers of these mammals would 
decline because of the loss of habitat. 

Increased diversion may have limited effects on the 
arboreal bats but squirrels may be detrimentally affected. 
Yeager (1949: 61) documented a shift from gray to fox 
squirrels as prolonged flooding killed trees resulting in 
the opening of timber stands at Calhoun Point Conservation 
Area, Jersey County. Squirrel numbers would be reduced if 
areas of bottomland timber are killed by higher water levels 
or if the composition of the bottomland forest communities 
change to more water- tolerant but less valuable species 
(cottonwood, willow, silver maple) for squirrels. 

Overall, increased diversion is expected to be detrimental 
to the small, ground- inhabi ting mammals and to most terres- 
trial species. Increased diversion may ultimately be bene- 
ficial to the semi-aquatic mammal species. From the economic 
viewpoint, raccoon and muskrat populations, the two most val- 
uable species of furbearers would probably be harmed and 
benefited, respectively. Populations of many of the other 
furbearers and small game species would probably be adversely 
affected. White-tailed deer would lose habitat if the amount 
of bottomland forest decreased. The magnitude of the changes 
caused by increased diversion is difficult to predict. 



14-1 



CHAPTER 14 : STATE AND FEDERAL AREAS, 
NATURE PRESERVES, AND NATURAL AREAS 



Several areas along the Illinois River are owned by the 
Federal Government, Illinois Department of Conservation, and 
the Illinois Nature Preserves Commission for conservation, 
recreation, or preservation. 

The Illinois Department of Conservation ovs'ns 19 areas 
that occur within the project boundaries. These conservation 
areas and state parks are used by the public for hunting, 
fishing, picnicking, bird-watching, hiking, and other out- 
door recreation. There are 4 federal wildlife refuges in 
the Mark Twain System within the project area that serve as 
valuable resting and feeding places for migrating waterfowl 
and shorebirds as well as several other species of wildlife. 
The names and sizes of these federal and state areas are 
presented in Table T'^-l . Their localities are shown in 
Figure 14-1. Both the Upper Pools and the La Grange Pool 
have 7 of these areas with the La Grange Pool containing 
the largest amount of land in these tracts (8,390 ha, 
20,722 acres). The state parks and conservation areas 
and federal refuges encompass a total of 21,466 ha (53,020 
acres) within the project confines. 

The Illinois Nature Preserves Commission owns land for 
preservat ional reasons in 6 areas that occur in the project 
area. Nature preserve property is maintained in its 
natural condition for educational and scientific purposes. 
The names, sizes, and locations of the nature preserves in 
the project area are presented in Table 14-2 and Figure 14-2 . 
A total of 1,762 ha (4,353 acres) of nature preserves occur 
within the project boundaries with 4 nature preserves totaling 
1,422 ha (3,513 acres) in the Upper Pools and 2 nature pre- 
serves totaling 340 ha (840 acres) in the Peoria Pool. 

In 1978, the Illinois Natural Areas Inventory was 
completed. This inventory was performed to provide detailed 
and accurate information concerning the locations and 
features of the principal remaining natural areas in 
Illinois. John E. Schwegman, Chief of the Natural Areas 
Section of the Illinois Department of Conservation, provided 



14-2 



Table 14-1. State Parks, State Conservation Areas, and. 
Federal Wildlife Areas in the Proj ect Area . ' 



Name of Area 



Hectares 



Acres 



Upper Pools 



1. Des Plaines Conservation Area 

2. Channahon Parkway State Park 

3. Goose Lake Prairie State Park 

4. W. G. Stratton State Park 

5. Gebhard Woods State Park 

6. mini State Park 

7. Buffalo Rock State Park 

Total 



1 ,721 .9 

7.3 

1 ,027.1 

2.4 

12.1 

206.5 

17.4 

2,994.7 



4,253 

18 

2,537 

6 

30 

510 

43 

7,397 



Peoria Pool 



8. Starved Rock State Park 

9. Cameron Division Mark Twain Wildlife 

Refuge^ 

10. Marshall County Conservation Area 

11. Woodford County Conservation Area 

12. Ft. Creve Coeur State Park 

Total 



1,021 .9 



3,752.7 



2,524 



257, 


.9 


637 


,264, 


.0 


3,122 


,174, 


.1 


2,900 


34, 


.8 


86 



9,269 



La Grange Pool 

13. Pekin Lake Conservation Area 

14. Spring Lake Conservation Area 

15. Banner Conservation Area 

16. Rice Lake Conservation Area 

17. Chautauqua Division Mark Twain 

Wildlife Refuge^ 

18. Anderson Lake Conservation Area 

19. Sanganois Conservation Area 

Total 



587.0 1,450 

787.9 1,946 

(in acquisition) 

1,059.9 2,618 



2,074 

863 

3,016 



5,125 
2,133 
7,450 



8,389.5 20,722 



Alton Pool 



20, 

21 , 
22, 

23, 



Meredosia Division Mark Twain 

Wildlife Refugeb 749.0 
Calhoun County State Conservation Area 498.8 
Calhoun Refuge Mark Twain Wildlife 

Refugeb 2,044.5 

Pere Marquette State Park 3,036.4 

Total 6,328.7 

Grand Total 21 ,465.6 



1 ,850 
1 ,232 

5,050 
7,500 

15 ,b32 

53,020 



Localities noted in Figure 14-1 
b Federal refuge. 



14-3 




le - ANDERSON LAKE CONSEBVATICK AREA 
19 - SAN5AN0IS CONSERVATION AREA 



CALHOUN COUNT* STATE CONSERVATION AREA 



P£R£ WIRQUEnE STATE PARI, 



Figure 14-1. 



State parks, state conservation areas, and 
federal wildlife areas located within the 
project area of the Illinois River valley. 



14-4 



Table 14-2. Nature Preserves in the Project Area. 



Name of Preserve 



1 . Cranberry Slough 



Upper Pools 



2. Cap Sauers Holdings Forest Nature 
Preserve 



5. Black Partridge 



4. Goose Lake Prairie 



Hectares Acres 



161.9 400 



615.4 1,520 



32.4 



80 



Total 



612.6 1 ,513 



1,422.3 3,513 



Peoria Pool 



5. Starved Rock 



235.6 



582 



6, Miller-Anderson Woods 
Total 
Grand Total 



104.5 258 

340.1 840 

1,762.4 4,353 



Localities noted in Figure 14-2 



14-5 



WISCONSIN 



IOWA 



LAKE MICHIGAN 



\ CHICAGO 



STARVED ROCK 



MISSOURI 



jl ^-^ 


' PEORIA 
LOCK & 
DAM 


^JD HAVANA 






1 - CRANBERRY SLOUGH 


y\:^^y^^^ 


2 - CAP SAUERS HOLDINGS FOREST 


%— 


NATURE PRESERVE 




3 - 6LAC« PARTRIDGE 




« - GOOSE LA<E PRAIRIE 




5 - STARVED ROCK 




6 - WILLER-ANDERSON WOODS 


GRAFTON 




7 ">^ ALTON 

*J LOCK t DAM 





Figure 14-2. Nature preserves located within the project 
area of the Illinois River valley. 



14-6 
Areas 



us with information concerning natural areas that occur in 
the project area. A total of 1,089 sites were identified in 
Illinois as natural areas and several of these occur along 
the Illinois River. We believe that 9 of these areas may 
be affected by the Diversion Project. Several other areas, 
such as hill prairies, occur in state parks and conserva- 
tion areas or on privately owned property at elevations 
that should not be influenced by increased water levels 
in the Illinois River. The names and sizes of the 9 natural 
areas that could be affected are presented in Table 14-3. 
The location of these natural areas is shown in Figure 14-3. 
These 9 areas encompass a total of 2,993 ha (7,993 acres). 
Five areas totaling 1,091 ha (2,69S acres) occur in the 
Peoria Pool, 3 areas representing 1,302 ha (3,215 acres) 
are located in the Upper Pools, and the remaining area 
encompassing 600 ha (1,483 acres) occurs in the La 
Grange Pool. Complete information on all of the natural 
areas identified in Illinois is incorporated in the 
Illinois Natural Areas Inventory. 



EFFECTS OF DIVERSION 



The effects of increased diversion of water into the 
Illinois River on the natural areas, nature preserves, state 
parks and conservation areas, and federal refuges would vary 
among these areas, and, therefore, are difficult to prog- 
nosticate. However, these areas are of major importance if 
increased diversion is undertaken because of their public 
usage and concern. These areas may require special monitorinj 
of increased diversion to note any subsequent effects on 
plants, animals, and public recreation. 



14-7 



Table 14-3. Natural Areas in the Project Area 



Name of Area 



Hectares Acres 



Upper Pools 

1 . Lake Calumet 

2. Lemont East Geological Area 

3. Wedron Palisades 

Total 



19.8 49 

1,275.3 5,145 

8.5 21 

1 ,301 .6 3,215 



Peoria Pool 
Starved Rock State Park 
Spring Lake Heron Rookery (De Pue) 
Senachvs'ine Seep 
Cameron Research Natural Area 
Spring Bay Fen 
Total 



601 .2 


1 ,485 


364.0 


899 


35.2 


87 


71 .7 


177 


19.0 


47 


1 ,091 .1 


2,695 



La Grange Pool 



9. Clear Lake Rookery 



Grand Total 



600.4 
2,993. 1 



1 ,483 
7,395 



Localities noted in Figure 14-3 



14-8 



WISCONSIN 






/ PEORIA 




J 


• LOCK 


K 




r^ 


DW1 






X, 








HAVANA 






- iA« cALimn 

- LEHONT EAST GEOLXICAL AREA 


V 






- WEDRON PALISADES 




■> 


B 
9 


- STARVED BOCK STATE PARk 

- SPRING LAKE HERON ROOKERY (DE PUE) 

- SENACHWINE SEEP 

- CAMERON RESEARCH NATURAL AREA 
. SPRING BAy FEN 

- CLEAR LAKE ROOKERY 



Figure 14-3. Natural areas located within the project area 
of the Illinois River valley. 



lS-1 



CHAPTER 15: INTRODUCTION TO THE AQUATIC STUDIES 
OBJECTIFIES 



The objectives of this chapter are to provide 1) a 
general description of the aquatic habitats of the Illinois 
Waterway, (which affect all of the aquatic organisms studied) , 
and 2) to explain the approaches that were used to assess 
the impacts of increased diversion on the individual major 
aquatic groups of the waterway. 



THE AQUATIC HABITATS OF THE ILLINOIS W^TERKAY 

The Illinois Waterway (a detailed description is given 
in Chapter 1) contains a diverse assemblage of aauatic 
habitats. A drop of water making a full trip through the 
waterway would originate in Lake ^'ichigan: pass through a 
series of rectangular rock-cut channels in the 
Chicago area; enter the geologically young and narrow unper 
Illinois River via the Des Plaines River: dramatically lose 
speed as it entered the broad, bottomland lake-strewn reach 
of the middle Illinois River, and return to a levee- 
constricted narrow channel before entering the vast ^Hssissippi 
River. Along its way, the drop of water would pass through 
a series of locks and dams which control the flow of the 
waterway and make it com.mercially navigable. The effects 
of increased diversion of Lake ^'ichigan water will be depend- 
ent upon the habitats being impacted and therefore a general 
description of these habitats and their distribution along 
the waterway is necessary. 

Aquatic Habitat Descriptions 

The following aquatic habitat descriptions were based 
on a classification scheme developed by the Upper ^'ississippi 
River Conservation Committee (U^^'PCC) (197Q) with the follow- 
ing exceptions: 1) Lake Michigan, and rivers and creeks 
(tributaries) were added because of their importance to 
the Illinois Waterway, and 2) the UMRCC "River Lakes and 
Ponds" classification was broken down into mainstem lakes 
and bottomland lakes to distinguish Peoria Lake (the only 
mainstem. lake on the Illinois Waterv;ay) from the numerous 
bottomland lakes of the middle and lower Illinois River. 



Aquatic Studies 15-2 

Lake Michigan 

Lake Michigan is the principal water resource of northeaster 
Illinois and represents the source of the diversion water. The 
nearshore of the lake consists of water less than 50 m in 
depth. Substrate types include hardpacked clay, sand, and rock. 
The lake shore is stabilized by steel pilings or concrete and 
rock rip-rap. Wave-induced turbulence is high. Aquatic 
vegetation consists of phy toplankton and of Cladocera attached 
to the substrate. 

Main Channel 

The main channel is maintained by dredging with a minimum 
depth of nine feet. Current always exists, varying in velocity ; 
with water stages. The substrate composition is a function of li 
water velocity. High velocities produce eroding substrates I 
(gravel and rock) and slow velocities produce depositing sub- 
strates (sand and silt). No rooted vegetation is present. 

>^ain Channel Border '' 

The main channel border is the zone between the main 
channel and the main river bank. The substrate consists of 
mostly sand in upper sections of the pools and silt in the lowerij 
sections. Little or no rooted aquatic vegetation is present, 

Tailwaters 



Tailwaters are located immediately below the dams and 
are characterized by increased turbulence from the passage of 
water through the gates and out of the locks. The substrate : 
consists mostly of sand. No rooted aquatic vegetation is presenii 

Side Channels 

Side channels include all departures from the main channel 
in which there is current during normal river stage. Substrate 
type varies from sand to silt. In the swifter current, there 
is no rooted aquatic vegetation, but vegetation is common in 
the shallower areas having silty substrates and moderate to 
slight current. 

Mainstem Lakes 

Mainstem lakes are widenings of the main channel and channel 
border. The river's velocity is slowed in this area causing 
deposition of sand and silt. Rooted vegetation is sometimes 
present in the littoral area. As noted earlier, Peoria Lake is 
the only mainstem lake in the waterway. Although Peoria Lake i 
has been filling with sediment at a slower rate than most of thel 
Illinois River's bottomland lakes (Bellrose et al , , 1979), this 



Aquatic Studies 15-3 

rate is still substantial. The lake has been almost devoid of 
aquatic plants since the late I950's (Mills et al . , 1966). 

Bottomland Lakes 

Bottomland (or backwater) lakes are bodies of standing 
water located in the floodplain of the river or stream. They 
often are created by the action of flow in the main river. 
Suspended materials are deposited, forming impounded lakes which 
are sometimes flooded during high water stages. The substrate 
of these lakes consists mostly of silt and sand. The bottom- 
land lakes of the middle Illinois River are being heavily 
impacted by sedimentation and few have aquatic vegetation. 

Sloughs 

Sloughs are intermediate between "bottomland lake" and 
"side channel" habitat. They may be former side channels that 
have been cut off or that have only intermittent connections 
to the main channel. They are characterized by having no 
current at normal water stage, a muck substrate, and variable 
amounts of submerged and emergent aquatic vegetation. 

Rivers and Creeks 

Rivers and creeks carry the run-off of the surrounding 
drainage area to the main waterway. The differentiation of 
rivers and creeks is very subjective. Creeks usually have a 
higher gradient and coarser substrate composition. The water 
volume of creeks is greatly affected by meteorological events. 
Rivers have a lower gradient (slower water velocity) and sand 
or silt substrate. They do not undergo the degree of water 
volume fluctuation seen in creeks. The presence of rooted 
vegetation in tributaries is dependent on the average water 
velocity in the waterway. 

AQUATIC HABITAT DISTRIBUTION 

Bellrose et al . (1977: C-3) provided surface areas for 
various types of aquatic habitats in six pools of the Illinois 
Waterway based on maps and photographs covering the period 
1969-1975. These data are presented in Table 15-1 to indi- 
cate how abundant the aquatic habitats are in these reaches 
of the waterv,'ay. 

Chicago-area reaches of the waterway above the Brandon 
Road Pool were not assessed by Bellrose (1977: C-3), but 
predominantly contain man-made channel and main channel border 
habitats. No mainstcm or bottomland lakes or sloughs exist 
in these reaches, which are also nearly devoid of side channels 
and tailwaters. The upper Illinois River (i.e., the Starved 
Rock Pool, Marseilles Pool, and part of the Dresden Pool) and 



Aquatic Studies 



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Aquatic Studies JS-S 

the Des Plaines River in the Dresden and Brandon Road 
Pools are largely made up of main channel and main channel 
border habitats but also contain small quantities of side 
channel and bottomland lakes habitats. Bottomland lake 
habitats characterize the Peoria and La Grange Pools of 
the watenvay, but they also contain main channel, main channel 
border, and side channel habitats. Peoria Pool contains the 
only mainstem lake (Peoria Lake, approximately 15,500 acres) 
of the waterway. The Illinois River reach of the Alton Pool 
formed by the Alton Lock and Dam on the Mississippi River has 
been constricted by numerous agricultural levees and therefore 
is not predominated by bottomland lake habitats but does contain 
main channel, main channel border, and side channel habitats. 
The Mississippi River reach of the Alton Pool is much wider than 
the Illinois River and contains main channel, main channel bor- 
der, and side channel habitats and a relatively smaller percen- 
tage of bottomland lake and slough habitats. Localized tail- 
water habitats occur behind each of the waterway's locks and 
dams below the Brandon Road Pool. Numerous tributary rivers and 
creeks enter the waterway along its entire length. 

AQUATIC STUDIES 

The general objectives of the aquatic studies were to pro- 
vide a biological inventory of the waterway's aquatic organism 
and to assess the impacts of increased diversion on them. The 
terrestrial studies described in Section II were directed 
towards investigating diversion- related changes in water quan- 
tity. Where possible, we have used the data provided in Chap- 
ter 4, under Terrestrial Studies, in assessing impacts on 
aquatic organisms related to water quantity changes. Aquatic 
habitats and organisms, however, are likely to be affected by 
changes in water quality as well as quantity. The water quality 
changes associated with increased diversion that may subse- 
quently impact aquatic habitats and organisms have been iden- 
tified (and when possible quantified) in Chapter 2. 

The major groups of aquatic organisms covered in this 
section are the algae (periphyton and phy toplankton) , zoo- 
plankton, macroinvertebrates , and fish. The approach used in 
studying each of these groups was dependent upon the availa- 
bility of past data for that group, the amount of time, man- 
power and funds available for sampling, and their suspected 
vulnerability to increased diversion effects. 

The lack of recent information on plankton populations 
throughout the waterway required a sampling program to generate 
comparable data from different stations. However, since the 
stations could only be sampled three times, we chose late 
summer months when the effects of diversion presumably would 
be greatest. 



ms 



Aquatic Studies J5-6 



The scarce macroinvertebrate populations of the waterway 
have been described in greater detail and more recently than 
its plankton populations. For this reason and the fact that 
sampling macroinvertebrates is both time-consuming and costly, 
the effects of increased diversion on them were estimated 
using available literature and data. 

More data exist for fish populations in the waterway 
than for any other aquatic group. Their importance from the 
standpoint of the river as an aquatic resource required that 
we not only continue our annual electrof ishing sampling 
program on the Illinois River, but that we also supplement 
this program with minnow-seine and hoopnetting methods. 
Recent fisheries data also enabled us to use a quantitative 
statistical method for relating the effects of water level 
changes to fish populations. In addition, water quality 
data for stations in the Chicago-area reaches of the water- 
way were used to assess the effects of diversion on the 
dilution of substances known to be toxic to fish. 

The chapters in this section were logically organized 
to: 1) discuss the current status of the aquatic group in 
the waterway; 2) to compare (when possible and if necessary) 
the current status of the group to their past populations; 
and 3) to discuss the impacts of increased diversion on the 
group in question in light of the estimated physical and water 
quality changes identified in Chapter 2. 



SECTION III. AQUATIC STimiES 



16-1 



CHAPTER 16: ALGAE (PERIPHYTON AND PHYTOPLANKTON) 

Larry K. Coutant and Nancv E. Coutant 
INTRODUCTION 

The algae, including the periphyton and phytoplankton, 
in the Illinois Katerv:av are of considerable importance for 
several reasons. Algae are primary producers and therefore 
represent a critical link for the synthesis of inorganic 
chemicals into organic products. They are a food source for 
not only the zooplankton and certain benthic macroinverteb- 
rates but also for larval fish and certain adult fish 
(Kofoid, 1903: 186, 563-565; Kofoid, 1905: 234; Forbes, 
1903 : 67; Forbes and Rich- 

ardson, 1913: 483, 487). Also, the algae produce oxygen which 
is required for respiration by aquatic animals at higher 
trophic levels and for microbial breakdown of sewage and 
other organic inputs. Both phy toplankton and periphyton 
also have considerable im.portance as water quality indica- 
tors (Bahls, 1973: 134; Palmer, 1957: 60; Round, 1965: 29; 
Lowe, 1974: 5; Reimer, 1965: 21; Patrick, 1965: 70; Purdy, 
1930: xiv) . Algae may multiply sufficiently to develop 
nuisance "blooms", and thus have the potential for causing 
water quality problems. Finally, algal decomposition by 
bacteria may deplete the oxygen needed for "higher" trophic 
levels' respiration (V.'illiams, 1964: 816; Palmer, 1962: 43; 
Kothandaraman and Evans, 1972: 1; Klein, 1962: 353), the 
end result being the mortality of fish. The objectives of 
this chapter were to describe and compare past and present 
algae populations in the IVaterway, to discuss the primary 
factors that influence these populations, and to predict the 
effects of increased Lake Michigan diversion on them. 

PAST MEASUREMENTS OF ALGAL POPULATIONS IN THE ILLINOIS RIVER 

Problems Connected with Comparing Results of Past Studies 

The following sources were used to review past algal 
populations in the Illinois River: Kofoid (1903), Purdy (1930), 
U.S. Public Health Service (1961 ) , Industrial Rio-Test 
Laboratories, Inc. (1972), Wapora, Inc. (1973), 



Algae ^^-2 

V;apora, Inc. (1974), and Colbert et al. (1975). Data from 
these sources were summarized in Table 16-1. Important factors 
to be considered in comparing data from different researchers 
are their methods of collection and enumeration. For examnle, 
data from Kofoid (1903: 253), as summarized in Table 16-1, 
represent the combined results of 2 collecting miethods vhich 
utilized either a planVton net (bolting cloth) or filter pads. 
Data of Purdv (1930: 34) were obtained from collections of 
vhole vater which were preserved and allowed to settle: thus 
his data represent all identifiable organisms which were present 
in the water. Data of Industrial Bio-Test Laboratories, Inc. 
(1972: 18) were obtained from water collected with a Kemmerer 
water sampler and thus represent essentially all algae present 
in the water. Data of the U.S. Public Health Service (1961: 67) 
were obtained from an aliquot of unprocessed water taken for 
bacterial analysis and m.ay represent all algae in the water, 
but specific m.ethods v.'ere not reported. IVapora , Inc. (1973) 
and Wapora, Inc. (1974) sampled with a lOy-mesh net ivhich al- 
lowed enumeration of the majority of algae present in the 
wate. but som.e of the smaller forms may have been lost through 
the net. Data bv Colbert et al. (1975) v.'ere obtained fromi 
net sar.ples taken with a No. 20 net and thus would represent 
the data with the greatest loss of organism;s through the net. 
The expression of data in standard cubic units per cubic centi- 
meter bv Purdy (1930: 36) also makes direct comparison of his 
data with other researchers almost impossible but relative 
comparisons within his study can be made. Other problems in- 
clude changes in taxonomy and different levels of expertise 
between researchers. 

Pre-1900 

When Kofoid did his work on the Illinois River in the 
late 1890's, the Illinois River was slow-moving and had many 
backwater areas that v.'ere ideal habitats for algal growth and 
reproduction. In fact, Kofoid (1905: 546-547, Vol. 1) stated 
that: 

Though continually discharging, the stream, main- 
tains the continuous supply of plankton, largely by 
virtue of the reservoir backwaters -- the great 
seedbeds from which the plankton-poor but well- 
fertilized contributions of tributary streams are 
continuously sov.n with organisms whose further 
development produces in the Illinois River a plankton 
as yet unsurpassed in abundance. 

Kofoid (1903: STO) stated that his collections indicated 
a period of m.inimum production of plankton in January-February, 
of rising production in ^^arch, of maximum production for the 



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year in April-June, usually culndnating in a vernal paxiiiiuin 
about the end of April and often declining rapidly to a low 
level in June. The average monthly production declined 
gradually during the remainder of the year to the winter mini- 
mum in December. The decline of plankton populations during 
the colder months in the river was indicative of a temperature- 
related phenomenon; in fact, Kofoid (1903: 572) noted that 
"Below 7.2 C the plankton content in the river is only about 
9 percent of that present above this temperature . . . ". 
Temperature is critical for algal growth and a large percen- 
tage of the algae in the Illinois River probably have optimum 
growth rates between 18 C and 40 C according to those tempera- 
tures suggested for various groups of algae by Cairns in Palm.er 
(1962: 56). Temperature probably becomes limiting for 
growth of Illinois River phytoplankton in winter months since 
water temperatures along the length of the Waterway are known 
to drop to C at various locations (U.S. Geological Survey, 
1977: 112-508). 



Post-lPOO 

After Kofoid's study, several changes occurred which 
had a negative effect on algal populations in the waterway. 
These changes included: (1) an increase in velocity in 
the river due to the diversion of Lake *'ichigan water through 
the Chicago drainage canal, (2) the leveeing of former back- 
waters for agricultural use ('*'ills, Starrett, and Bellrose, 
1966: 3; Forbes and Richardson, 1919: 146-147: Purdv, 1030: 4) 
(3) increased tillage of agricultural uplands and an increase 
in barge traffic, thereby increasing the silt load and 
turbidity in the river (Mills, Starrett, and Fcllrose, \^^6: 
3-7), (4) additions of sewage and wastes in the Chicago area 
and the "flushing" of these additions down the Illinois 
River bv the Lake ^Uchigan diversion. These additions of 
sewage in the Chicago area have been the subject of inves- 
tigation by several authors. 



A 1 n a e 



16-8 



Earlv investigations hv TTorbes and Richardson (IQIZ) 
according to Purdv (1^30; 13-15) related polluted conditions 
in the waterway to the algal flora. Those authors stated 
that the sanitary canal at Lockport and the Pes Plaines River 
at Lockport were characteristically "septic". There were 
scattered algae along the edge of the sanitarv canal, and 
there were frequently Muegreen algae attached to the hotton- 
stones in that vicinity. The waterv;ay was polluted from the 
Des Plaines River at Dresden Heights to ^^arseilles with a 
frequent predominance of the Muegreen algae Osci llatoria 
and Phormidium . They considered the river contaminated at 
^^arseilles where Muegreen algae were common hut less so at 
Starved Pock where the green algae were starting to increase 
and the bluegreens were decreasing in importance. ^rom 
Starved Pock to Chillicothe, Forbes and Richardson considered 
the water to be relatively unpolluted and there was a pre- 
dominance of green algae. 



The only rese 
the waterway was P 
the July, 1922 and 
indicated moderate 
canal (mile 29 2) a 
phytoplan"- ton cone 
Bridge (mile 286) 
densities in that 
generally with the 
pollution was gene 
There was a gradua 
from Morris all th 
considerable drop 
water reached mile 



archer to study a considerable length of 
urdy (1930). As can be seen in Table 16-1, 

August, 1922 data of Purdv (1930: 198) 

populations of algae in the Chicago drainage 
t Lockport and a gradual decrease in 
entrations to the area around the Brandon 
and Morris (mile 263) . The lowest 
stretch of the Illinois River agrees 

belief of Purdy that considerable 
rally in the area of ^^orris and La Salle. 
1 increase in phytoplankton abundance 
e way to Havana (mile 166) and then a 
in phytoplankton abundance by the time the 

25 (below Kampsville) . 



A Igae 



16-Q 



Purdv C1930: 59) felt that considerable amounts of 
pollution vere being added in the upper Illinois River svstein, 
but Lake Michigan water diluted the polluted water and manv 
"clean water" algae were present in the Chicago drainage 
canal as a result. The Illinois River was most heavily 
polluted in the vicinity of Joliet, ^'orris, and La Salle 
according to the large numbers of "pollutional forms" present 
in the water at those locations but bv the time the Illinois 
River water reached Chillicothe, there was a noticeable 
improvement in the water quality and there was a change in 
dominant organisms to those forms more characteristic of 
clean water (Purdv, 1930: 50). Purdv also mentioned that 
the lower river showed a much greater diversitv of plankton 
than the upper river. Purdv felt that there was then an 
increase in pollutional forms and peak plankton production 
at Havana due to the sewage input from Peoria and Pekin 
(Purdv, 1930: 49). He mentioned that the river downstream 
from kampsville was "fairly clean" (Purdy, 1930: 164). This 
statement was supported by the large variety in taxa and the 
relatively few numbers of pollutional forms observed in the 
plankton there (Purdy, 1930: 174). According to the data 
presented by Purdy (1930: 199-212), green algae were the 
predominant algae at all stations along the whole length of 
the river. The other major groups of algae as listed bv 
Purdy indicated that diatoms were the second most abundant 
group of algae and bluegreen algae and flagellates were also 
common at all stations (Purdy, 1930; 199-212). 



Between the 
the Public Health 
were added at vari 
Illinois River sys 
Dresden Heights (2 
(19 ft.) , Peoria ( 
as a navigational 
(^411s, Starrett, 
several influences 
and success of phy 
(1903: 111) stated 
for they check the 
low water, facilit 
volume of \\-ater at 
tend to increase t 
effective at low-w 
dissolved oxygen i 
the various spillw 
to passage over th 
If, hov;ever, the w 
would have been ad 
dams. The dams al 



time of Purdv 
study in 1961 
ous locations 
tern. The sit 
2 f t . ) , >7arse 
11 ft.), and 
dan on the ^'i 
and Bellrose, 

on rivers wh 
toplankton as 

that " . . . 

current , del 
ate the depos 

lov.'-water st 
he production 
ater stages." 
n the water a 
ays : i f the w 
e dam, the re 
ater v.-as unde 
ded to the wa 
so had the ef 



' s study (i.e. , 
, a series of na 

along the lengt 
es of these dams 
illes (24 ft.). 
La rrange (10 ft 
ssissippi River 

1966: 5). ^'ost 
ich are importan 

well as periphv 

dams are of gre 
av the run-off, 
ition of silt, a 
ages . All of th 

of plankton and 
Also, the dams 
s a result of pa 
ater was supersa 
suit would be a 
rsaturated, diss 
ter after nassag 
feet of changing 



the 1920's) , and 
vigational dams 
h of the 

were at 
Starved Rock 
.) , as well 
at Alton 

dams have 
t to growth 
ton. Kofoid 
at importance, 
especiallv at 
nd double the 
ese factors 

are most 

affected the 
ssage over 
turated prior 
loss of oxvgen. 
olved oxvgen 
e over the 

the river 



Algae 16-in 

environment into a seiri-lotic environment consisting of a 
series of eight pools with varying water velocities within 
and above each pool. The pooling probably had a positive 
effect on the algae because the greater retention time along 
the river allowed greater populations of algae to develop in 
the upper lavers of water (i.e., the cuphotic zone). A lacV 
of m.ixing of upper layers of waters with deeper waters in the 
Illinois River could probably lead to considerable algal pro- 
duction in the upper lavers of waters and the development of 
nuisance blooms but according to Wang (1974: 10), "the eunhotic 
zone is constantly being mixed and diluted with less algae 
populated waters from the deeper strata, the aphotic zone. 
This mechanism lessens the probability of algal blooms." 
The dams of course deepened the water upstream from their 
respective locations on the river and the deeper waters have 
reduced temperatures; lower temperatures are Vnown to hinder 
the breakdown of pollutants (organic compounds) into forms 
that can be used by the plankton (Forbes and Richardson, 1919: 
144). Also the creation of dams also allowed more barge 
traffic; this traffic has influenced the turbidity (^'ills, 
Starrett, and Bellrose, 1966: 5) which has been shown to 
retard algal growth in the Illinois River (Wang, 1974: 1). 

The U.S. Public Health Service sampled a considerable 
stretch of the Illinois waterway svstem although their efforts 
were limited to the river system in the Chicago area including 
the North Branch, Chicago River, and Calumet River with 
several sampling points along each of these branches and 
several stations below their various junction points to the 
Dresden Dam. A summary of the phvtoplankton data which was 
collected in April and ^^ay 1961 indicates that the highest 
phytoplankton densities were generally at the points of entry 
of Lake ^'ichigan water and there were considerable declines 
in the phytoplankton populations by the time the water 
reached the Dresden Dam (Table 16-1). There were, however, 
considerable fluctuations in phytoplankton concentrations 
along certain stretches of the various waterways in the Chicago 
area indicating brief recovery periods or increases in 
certain areas but the overall trend In the Chicago ^'etropol i tan 
area was that of a decrease in phytoplankton populations as 
the water flowed downstream. 

The U.S. Public Health Service (1961: 4) stated that 

The Illinois Waterway in the vicinity of (Greater 
Chicago in its present state is polluted. The 
waterway remains seriouslv degraded through the 
Brandon Pool. Recovery begins in the Dresden 
Island Pool where the Kankakee River joins the 
Des Plaines River to form the Illinois River. 



Algae 



16-11 



^fore specifically, in regard to the phytoplanl- ton, the U.S. 
Public Health Service (1961: 5) stated' that pollution in the 
Chicago >!etropolitan area vas indicated by "Clean v;ater 
plankton diminishing and being replaced by pollution tolerant 
forms on proceeding downstream from the lake." The U.S. 
Public Health Service (1961: 67-68) also stated that 



At 1','ilmette and Chicago Harbor, imm 
lockages, phytoplankton counts were 
The numbers of phvtoplankton per mi 
suppressed once the flowing water c 
suspended aquatic plants entered re 
sewage treatment plant outfalls, st 
flows and other wastes of man-iriade 
the Illinois Waterway in the reach 
The counts are also suppressed at t 
Harbor entrance by industrial waste 
suppressed in this tributary of the 
of waterways. The plankton counts 
served immediately within the locka 
^!ichigan . . . are representative o 
water in the canal system .... 
water by pollution that results in 
at other stations reflects the pres 
garbage components, and oils, and o 
municipal and industrial wastes res 
activities in the area. 



ediatelv below 

highest . 
1 liliter were 
arrving such 
aches where 
orm water over- 
origin enter 
under study, 
he Calumet 
s, and remain 

canalized system 
that were ob- 
ges from Lake 
f the clearest 

Degradation of 
lower counts 
ence of feces, 
ther unidentified 
ulting from man's 



As previously mentioned, there are without doubt a 
multitude of toxic comipounds present in the Illinois River 
and one might suspect these to have considerable influence 
on algal grov/th (i.e., inhibition). Heavy metals have been 
rejected by Wang (1974' 1) as a primary cause for limitation 
of algal growth in certain sections of the Illinois River 
but the limited literature on the effects of the various 
other toxic compounds present on the Illinois River algae 
limits further discussion of toxicity as a factor. 

Data of Industrial Bio-Test Laboratories, Inc. (1972) 
(Table 16-1) in the vicinity of the junction of the Des 
Plaincs River with the Kankakee River and the Illinois 
River near the Dresden Nuclear Power Station in August 1970 
and August 1971 indicated that the phytoplankton densities 
were greater than those found at the Dresden Dam bv the U.S. 
Public Health Service in 1961. These differences were most 
likely seasonal differences since phytoplankton densities in 
a river such as the Illinois "iver would likely be lower in 
April and Kay than they would in August. 

Data of Wapora, Inc. (1973) (Table 16-1) from collections 
in 1972 indicated a general trend of decreasing phytoplankton 



Algae 



16-12 



densities from their sampling station at Hennepin, IlHnois 

dovn the river to their sites of ^^IJ^ction at Havana and 

near Meredosia, but data of Wapora, Inc. (1974) (Table 16 1) trom 

collections in 1973 indicated a reversal m this trend. 

Comparison of this data with that of Kofoid (1903) indicates 

that the phvtoplankton densities found bv Kofoid were vithm 

the range of values observed by ^''apora. Inc. in 1972 and 1973. - | 

The data of Colbert, et al . (1975) which was collected ' 
n July and September 1974 from the lower Illinois River 
(miles 23.1 through 81. n) indicates a tremendous decreases 
densities of phvtoplankton in that area of the Illinois ^iver 
(liable I'^-l), in comparison to data bv other researchers. This 
difference can be partially related to methods, however, since j 
Colbert, et al. (1975) collected phytoplanl<ton with a net 
having a much larger mesh size than other researchers. The j 
trend of lower phy toplankton populations in the lowerriver 
than upstream locations may be real but cannot be positively 
substantiated by comparisons of these and other data. 

Data by Wapora, Inc. (1974) and Colbert et al. (1975)_ indicate 
that a considerable variety of algae exists in the Illinois 
River based on the taxa recorded by these groups of researchers. 
Data by Wapora, Inc. (1974) indicated that members of the Bacilla- i 
riophyta (.diatoms) were the predominant group ot algae found ; 
in the Illinois River at locations near >'eredosia, Hennepin, I 
and Havana, Illinois. Data by Colbert, et al. (1975) ^^J^' ' 
cated that the Chrysophyta, including the diatoms, was the 
most common group of algae in the lower Illinois River and 
green algae, bluegreen algae, and euglenoids were less important 
but still common memb^ -s of the phvtoplankton . 

CURRENT STATUS OF ALGAE IN THE WATERWAY 

In order to determine the present condition of the phvto- 
plankton and periphvton in the Illinois River system, a 
sampling program was undertaken in 1978 at 13 sampling loca- 
tions along the waterway (figures 16-1 and 16-2). The sampling 
locations used for periphvton and phvtoplankton during 
July 17-19, August 14-16, and September lo-20, 1978 were as ; 
follows. Station 1 was located on the North Branch (river mile 
331.5) approximately .9 miles inland from the lock located on 
Lake Michigan. Station 2 was located just inside the lock , 
separating Lake Michigan from the Chicago River (river mile 2Z7J. j 
Station 3 was located at river mile 308 on the Sanitary and 



Ship Canal and was thus the next station downstream from 
Station 2 (Chicago River). Station 4 was located on the Cal- 
channel at river mile 308.5 and was located approximately 25 



Sag 



Algae 



16-13 



,, -.LMETTE 

UKE 
niCHlGAN 




Figure 16-1. Chicago Area Waterways. Plankton and Periphyton 
Sampling Stations. 



Algae 



16-14 




O = cniEs 

= LOCk »ND DAM SITES 
= SAMPLING STATION 



Figure 16-2. Illinois IVaterway. Plankton and Periphyton 
Sampling Stations. 



Algae • 16-15 



miles inland from the inlet from Lake ^'ichigan. Station 
5 was located just upstream from the lock located at Lock- 
port on the Sanitary and Ship Canal ("river mile 291"). 
Station 6 was located upstream from the Brandon Road Lock in Joliet 
(river mile 286) and Station 7 was located upstream from 
the Dresden Lock belou- the confluence of_the Des Plaines and 
Kankakee rivers at river mile 271.5. Station 8 was located 
upstream from the lock located at ^larseilles at river mile 
244.5. Station 9 was located above the lock at Starved 
Rock at river mile 231 and Station 10 was located above 
the lock at the southern end of Peoria Lake at river m.ile 
158. Station 11 was located upstream from the La Grange 
lock at river mile 80 and Station 12 was located near 
Kampsville (river mile 32) during July and near Michael's 
Landing (river mile 27) during August and September due to 
periphyton sampler vandalism during Julv at Kampsville. 
Because of similarities between flow, all samples fromi 
Station 12 were considered comparable. Station 13 was 
located near Royal Landing and was actually in pool 26 of 
the ^lississippi River. Stations 1. 3, 4, 12, and 13 
were located in areas of the river svstem which were no- 
ticeably flowing while all other stations were located 
upstream from locks in impounded, slowly- flowing water. 

Duplicate water samples for phvtopl ankton analvsis 
were taken in the Illinois River system at the stations 
listed during July, August, and September 1P78. The 
sam.ples were taken in the upper meter of water using a 
Kem.merer water sampler as described in Standard Methods 
(American Public Health Association, 1976: ini2), preserved 
with acidified Lugol's solution (Vollenveider, 1974: 7), 
and allowed to settle to concentrate the phvtoplankton . 

The concentrated samples were examined at 400X in a 
Palmer-Maloney nannoplankton cell (Keber, 1973: 9). Known 
volumes were examined and all algae were identified and 
counted using appropriate keys. All phvtopl ani-- ton were 
identified to the lowest possible taxon, with the exception 
of the diatoms which were counted and identified to major 
taxonomic groups and more specifically identified on pre- 
pared slides. The following unit counting svstem was used to 
enumerate the algae in the initial counting procedure: 

Algal Type Counting Unit 

Unicellular algae f- diatoms Each cell as 1 unit 

Colonial algae (including 4 cells/unit except bluegreen 
Stigeoclonium) colonies with cells<2p diameter 
(50 cells/unit) 



Algae 

Alpal Type (con't.) Counting Unit (con't.) 

Filamentous algae inOvi lengths as 1 unit 

The diatoms vere cleaned using a method from '^'an der 
Kerff (1953: 276-277) and mounted on slides with Hyrax 
mounting medium. The diatoms K'ere identified at l,noox 
using appropriate kevs . Proportional counts were used 
to determine concentrations of diatoms in the original 
sample as described in Standard ^^ethods (American Public 
Health Association, 1976). The procedure for analvsis of 
algae previously described was a modification of methods 
proposed by Weber (1973) . 

Periphyton collections were made using artificial 
substrates (i.e., glass slides) which were exposed at a 
depth of n.025 m below the water surface using a flotation 
device for a period of approximately one month. Periphvton 
substrates were placed at the 13 river locations listed 
previously in July and again in August 1978. Periphvton 
substrates placed at Station 5 (Lockport) in July were 
collected after two months exposure due to study area 
inaccessability during August 1978. Substrates were lost 
at Stations 3, 6, 7, 10, 11, 12, and 13 between July place- 
ment and August collection and at Stations 2, 4, 5, 6, 9, 
and 13 between August placement and September collection. 
The substrates at Marseilles (Station 8) and Starved Rock 
(Station 9) placed in July were retrieved after tv.'o rionths 
exposure due to dynamite blasting in August and the inabil- 
ity to retrieve them at that time. The substrates were 
preserved in the field with acidified Lugol's solution, 
transported to the laboratory, then scraped with a razor 
blade to remove attached algae. The scrapings were mixed 
in a Waring blender to break up clumps of algae: the 
slurry was adjusted to a know volume and counted using the 
phy toplankton procedure. 



RESULTS 

The predominant group of algae found in the phvtoplankton 
and periphyton of the Illinois River during July, Aucust, and 
September 1978 was the Baci llariophta (diatoms) (Table 
16-2 and 16-3). This group of algae is common to many 
freshwater habitats as are the Chlorophyta (green algae), 
Cyanophyta (bluegreen algae), Euglenorihvta (euglenoids) , 
Chrysophyta (yellow- green algae), and the Cryptophyta 
(cryptomonads) which were also common during the study period. 



16-17 



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43 
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Algae 



16-11 



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3 


a> 


•H 




+-> 


o 


i-i 


o 


c 


« 


<D 


•H 


MrH 


l-H 


I— ( 


t— ( 


I— 1 


CO 


O 


1— ( 


(3 


ex 


trt 


o 


4-> 


<D 


+-> 




•H 


>^c 


•M j:: 


• H 


•H 


p. 




tn 


• H 


OO 


c 


t- r~- 


<D 


(U 


cr. 


O Cu 


T— 






LO ,— ,— (NJ rsl LO 



r-a LO (Ni vo to 



CsJ CTi vO OO "3- 
r^ CT) to LD ':!■ 
t^ (N) (-0 r- LD 



,— ro 00 C5 
hO rJ ■^ »— 



^ 




x: 


r>a 


p 


^3- 


o 


CS) 


Vi 


•- 


o 


LO 


l-H 




X 




u 




e: 




o 




• H 




4-> 




rt 


«— 


4-> 




W 






4-> 




Cfl 


O 


3 


+-> 


bo 


rt 


3 


O 


< 



\0 00 LO to vD LO 



o OO r^i rj to 
rsi vo CTi \0 vO 



T— t^ 

■•— o 



00 c. «— t^ f^ '^ '^ 

T— (Nj OO en LO ^1" vc 
\0 c^ ^— CT> ^— t^ '•~ 



CO t^ '^ o3 



vD vC* 1— \C 



to »— 

r— tNJ 



cn vo <^ f^ 

CD to vD ^ 

00 Ln 00 cr> 



(N) ,— vo 



v£j 00 vo 



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a; 

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a> 

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o 






Algae 16-20 

Numerous algal taxa were identified in the Illinois 
Watervay from phytoplanVton and periphyton collections 
(Appendix E, Table E-3, E-4). ^'anv of these species were 
common to several river locations although there were notice- 
able differences in spatial distributions of certain taxa. 
Tabellaria fcnes trat a (Lvngbve) Kiltzing, T abel ] aria f locculosa 
(Roth) Kutzing , Cyclotella comta (Ehrenbergl Kutzing , Cvclotell^ 
ocellata PantocseV , Cvclotella Kutzingiana Thwaites, 
As terionella formosa H a s s a 1 1 , and Asterionella f ormosa v . 
gracillima (Hantz.) Hrunow were most abundant or found exclu- 
sively in the upper reaches of the waterv/av (Appendix E, 
Table E-3) in the phytoplanVton collections. These taxa 
were apparently present in Lake ^Uchigan and as a result of 
diversion and seepage through the locks were present in the 
Illinois river system at locations near the lake. Due to 
changes in environmental conditions in the water during passage 
downstream, these taxa were not able to survive in sufficient 
numbers to be detected at the river locations in the lower 
portion of the Illinois Piver. 

In general, the lowest numbers of taxa were observed in 
the phvtoplankton collections from the North Branch (Station 1) , 
the Chicago River (Station 2), and the Willow Springs location 
(Station 3) during the three sampling periods (Table 16-4). 
There was an increase in the number of taxa observed at most 
stations downstream from those locations probablv as a result 
of additions of phytoplankton from various sources along the 
river although Poyal Landing (Station 13), ^'arseilles (Station 
8), and >'ichael's Landing (Station 12) had low numbers of taxa 
present in the July, August, and September collections 
respectively. Greatest numbers of taxa were often present in 
the section of the river from the lock near Joliet (Station 6) 
to Peoria Lake (Station 10) . 

The phytoplankton diversities (Table l6-?)» computed 
according to the formula of Shannon (l'^48: 416), were lowest 
at the Chicago area stations down to the Lockport lock and 
generally increased downstream. The greatest declines in 
diversity were at the Willow Springs, Cal-Sag, and Lockport 
stations (Stations 3, 4, and 5) in August 1978 which was a 
result of predominance by minute coccoid green algae. The 
dominance of this group of organisms mav have beer the result 
of a stress situation upstream from the Willow Springs location 
since a gradual im.provemicnt in diversity was noted downstream 
to Marseilles (Station 8). Another dramatic decline in 
diversity was noted at Starved Rock (Station P) in August 1Q78. 
where coincidentally there were the greatest densities of 
phvtoplankton of all stations sam.pled during August (Table 16-2). 
This lowered diversity was a result of a bloom of primarily 
Aphanocapsa spp. N*^geli that occurred after barge traffic had 



Algae 



16-21 



Table 16-4. Total number of taxa identified from phyto- 
plankton and periphyton collections made at 
13 sampling stations in the I 1 1 inois War ervav 
during .lulv, August, and SeptemV^er 1P78. 





Phy 


toplan 


kton 




Periph) 


ton 


Station 


July 


Aug. 


Sept. 


^ug . 


Sept. 


Sept, 


1 


29 


31 


33 


44 


20 




2 


36 


32 


31 


57 






3 


49 


26 


31 




35 




4 


42 


28 


55 


53 






5 


45 


42 


54 






53 


6 


65 


44 


55 


-- 






7 


53 


72 


56 




56 




8 


51 


48 


30 




52 


73 


9 


75 


55 


59 






SI 


10 


43 


51 


57 




37 




11 


44 


49 


40 




45 




12 


51 


53 


30 




32 




13 


35 


44 


39 









-- indicates missing data 
* 2 month exposure 



Algae 



16-22 



Table 16-S Diversity indices of the phy toplankton and 
periphyton collected at 13 stations in the 
Illinois V.'rterwav during July, August, 
and September 1978. (*Peplicate 2 of Station 
3 in September for phytoplankton was lost 
during processing.) 







Diversity Indices 




Station 


Rep 1 


Rep 2 


Mean 


Phytoplankton__ _ 




July 





90 
24 
05 
57 
44 
01 
89 
70 



38 
50 
18 
13 
18 
92 
18 
83 



14 
37 
62 
85 
31 
96 
03 
76 



9 

10 
11 

12 
13 



4.30 
3.41 
4.33 
3.66 
3.48 



4.56 
3.56 
3.81 
3.86 
3.97 



4.43 
3.49 
4.07 
3.76 

3.73 



Phy toplankton August 



1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 



81 
25 
85 
95 
34 
24 
78 
97 
48 
27 
87 
89 
57 



17 

43 

53 

83 

45 

,14 

91 

,08 

,49 

,74 

,75 

,72 

,66 



49 
34 
69 



1.89 



40 
19 
84 
02 
48 
50 
81 
81 
61 



Phy top lank ton ??Pt?'pber 



02 
91 
41 
84 
68 
39 
55 
42 
26 



67 
41 

73 
17 
24 
92 
93 
65 



,85 
.66 
41 
,78 
.92 
.31 
.23 
.18 
.45 



Algae 



16-23 



Table 16-5 (continued) 



Station Diversity Indices 
Phvtoplankton Rep 1 Rep 2 Mean 

10 4.33 4.23 4.28 

11 3.94 3.78 3.86 

12 3.68 3.26 3.47 
__13 3.93 4.00 3.96 

Periphyton August ?§ day _ exposure 

1 4.14 5.53 3.83 

2 3.95 2.91 3.43 
___4_ 4.13 ...3:64__ ...?:88 

Periphyton_ September ?§. day expo sure 

1 2.71 2.81 2.76 

3 3.85 3.60 3.73 

7 4.76 2.77 3.76 

8 2.52 2.79 2.65 

lU 3.08 3.58 3.33 

11 3.48 3.65 3.56 

12 2,99 3,58 3,29 

Periphyton September §5. day expo sure 

5 4.51 2.60 3.55 
8 3.34 3.41 3.37 
Q 4 ,11 7 . 69 .3.4 



Algae 16-24 



been halted for a few weeks allowing suspended solids to settle. 
These events increased availability of sunlight and apparentlv 
tremendously increased phy toplankton productivity. It was 
noted by lock personnel along that stretch of the Illinois 
River that there were tremendous diurnal fluctuations in vU and 
dissolved oxygen during this period as a result of the bloom. 
During the follov;ing month, noticeable declines in diversity 
occurred at both "arseilles and Starved Pock where barge 
"raffic bv then had been halted for a period of almost two 
...onths. Again, these stations had the highest densities of 
phytoplankton recorded for that collection period and the 
high densities could at least be partially attributed to 
cessation of barge traffic, decreases in suspended solids, 
increases in available light and increased phy torilankton 
productivity of a few taxa. The dominant taxa at those two 
stations during September 1^78 were Cvclotella meneghiniana 
Kutzing at ^larseilles and Microcystis incerta Lemmerman and 
Aphanocapsa spp. at Starved Pock. 

The phvtoplankton blooms which occurred at those two 
stations during the study period illustrate the potential 
for algal growth in the Illinois Piver and the possible rela- 
tionships between barge traffic, suspended solids and limi- 
tation of photosynthesis due to lowered light availability. 
The limitation of algal photosynthesis by turbidity in the 
.Illinois Piver has been pointed out by V>'ang (1^74: 1) and 
the probable relationship between barge traffic and resus- 
pension of silt in the Illinois Piver has been mientioned by 
other researchers including Mills, Starrett, and Bellrose 
(1966: 5). All factors must be weighed carefully, however, 
since in July the greatest phytoplankton densities in the 
waterway occurred at Starved Pock (Table 16-2) and during that 
time there was normal barge traffic along that portion of the 
river. 

The densities of phytoplankton in the waterway were 
generally lov.'est at the three uppermost stations (i.e., the 
North Branch, the Chicago River, and the V.'illow Springs location) 
Phytoplankton densities in general gradually increased to 
peak concentrations in the Starved Pock area and then declined 
downstream from that location (Table 16-2). The low densities 
of phytoplankton at the locations near Lake ^'ichigan can ^e 
related to low densities of organisms in the lake A-;ater being 
diverted into the waterway through the locks. The gradual 
increase in densities downstream can be attributed to greater 
nutrients in the river system than Lake ^'ichigan in conjunction 
with sufficient retention time in the pools created by navi- 
gational locks which allowed for population growth and also the 
inflow of waters from tributary streams with dense populations 
of phytoplankton into the Illinois ^iver. 



Algae 16-25 



The decrease in phvtoplankton densities at stations 
downstream from Starved Rock were most likely related to 
increased mortality, mixing of the v;ater column more thorouphlv 
such that the surface waters in impounded areas with greater 
densities than deeper waters would he diluted, dilution of 
the river water with incoming waters which were more sparselv 
populated v;ith phvtoplankton , and decreased productivity of 
the phytoplankton due to an increase in turhiditv which was 
detected for downstream stations using Secchi disc transnarencv 
(Table 16-6), or any combination of the above mentioned 
factors . 

The periphyton collected from artificial substrate? (i.e., 
glass slides) were collected from three stations in August 
after 28 days of exposure, seven stations in September after 
approximately 35 days of exposure, and three stations in 
Septemiber after approximately 63 days of exposure (Appendix E, 
Tables E-2 and E-4) . The numbers of taxa recorded from the 
North Branch (Station 1) were the lowest of the stations 
collected during the 28-day and 35-dav exposures (Table 16-4). 
The density of periphvton on the glass slides was the greatest 
of all stations sampled in Septem.ber (35 day exposure) at the 
North Branch location. Those high densities were due to primarily 
the predom.inance of Sti geoclonium spp. Kutzing, nomnhonema cf . 
angustatum. Kutzing (Rabenhorts) , and noipphoner'a parvulum Kutzing 
which also resulted in that station having the second lowest 
mean diversity (2.76) of the stations sampled during that 
month (Table 16-5). Species which were found in the upper 
river locations in the periphyton but not in the lower Illinois 
River included Eunotia spp. Ehrenberg, Cyclotella ocellata , 
Cyclotella kutzingiana , Fragilaria crotonensis KTtton, and 
Tabellaria fenestrata . 

Because periphyton v;ere collected from artificial sub- 
strates near the surface, the actual composition and abundance 
of periphyton growing on natural substrates (i.e., the river 
bottom) in the Illinois River system is unknown. Several 
generalizations can be made from the available data, however. 
Since the growth of periphyton is limited to the river bottom 
in areas where light is sufficient, the periphvton would be 
abundant at depths proportional to the measured Secchi disc 
transparencies (Table 16-6). Since the compensation point (i.e., 
depth at which algae can maintain themselves) is from 2 to 
5 times the depth of the Secchi disc transparency in manv 
fresh water environments, periphyton growth would be limited 
to the shoreline and only slightly below the surface at 
several stations sampled in the lower river. In the upper 
river, particularly at Station 2 (on the Chicago River) good 
growth of periphyton would be possible at much greater depths. 



Algae 



16-26 



Table 16-f^. Secchi disc transparencies (m) at 13 

stations sampled for phytoplankton and 
periphyton in the Illinois H'aterv.'av 
during July, August, and September 1978 



Station 



July 



Aug 



Sept- 



1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 



1.15 
1.95 
0.87 
0.73 
0.87 
0.38 
0.40 
0.19 
0.42 
0.11 
0.20 
0.09 
0.13 



0.80 
1.80 
1.33 
0.90 
1.00 
1.04 
0.62 
0.65 
0.40 
0.70 
0.66 
0.23 
0.16 



0.27 
2.25 
0.53 
0.31 
0.49 
0.58 
0.40 
0.48 
0.16 
0.20 
0.19 
0.18 



-indicates missing data 



Algae 16-27 



Linear regression analyses were performed using Secchi 
disc transparency (m) (Table 16-6) as the independent variahle 
and phytoplanVton total densities (averaged from 2 replicates, 
Appendix E, Table E-1) as the dependent variable to determine 
if a significant correlation existed between the two variables. 
In July 1978, the correlation coefficient for the regression 
line was -.5298 and the t statistic using 11 degrees of 
freedom was 2.0717, The correlation coefficients for the Aug- 
•^st and September 1978 data were -.6068 and -.2997, respectively. 
The t statistics for those dates were 2.5321 (11 degrees of 
freedom) and .9936 (10 degrees of freedom), respectively. 
Only the August data was significantly correlated (0.05 level) 
with Secchi disc transparency although all three months had 
negative correlations. The data indicates that at least 
during August there was an inverse relationship between Secchi 
disc transparency and phytoplankton densities. It is not 
completely understood why the greater phytoplankton densities 
were associated with water which was more turbid. 'Perhaps 
the greater nutrients associated with more turbid waters allowed 
development of greater densities of phytoplankton in the upper 
layers of water. 

Phytoplankton population development in the upper waters 
would also have beer aided by the limited mixing of the water 
column due to location of many sam.pling stations in stagnant 
waters above locks. Since phytoplankton contribute to tur- 
bidity, greater densities of them also could have contributed to 
reduced Secchi disc transparency. 

Linear regression analyses were performed using zoo- 
plankton total densities as the dependent variable and 
phytoplankton total densities as the independent variable. 
The correlation coefficients for July, August, and September 
1978 data were 0.6883, 0.6643, and 0.2521, respectively. The 
t statistic values for those same months were 3.1468 (11 degrees 
of freedom), 2.8102 (10 degrees of freedom), and 0.8239 (10 
degrees of freedom), respectively. Both the July and August 
data indicated a significant correlation (0.05 level) between 
the phytoplankton densities and zooplankton densities. It 
seems that generally the phytoplankton and zooplankton had 
highest densities at the same river locations which indicates 
that conditions which favored growth of phytoplankton popu- 
lations may have also favored growth of zooplankton. 

PROBABLE ET^t:eCTS OF INCPFASED DIVERSION ON THE ALCAE OF 
THE ILLINOIS RIVER 

The diversion of increased amounts of Lake ^'ichigan water 
into the Illinois Waterway during the low- flow summer months 



Algae 



16-28 



would 
featu 
stanc 
ducti 
benef 
algae 
s ince 
l<noKn 
the p 
study 
Anoth 
backv 
resul 
creas 
be an 
for o 
sumer 



have 

re of 

es in 

vity a 

it the 

for f 

Wang 

to be 

rimary 

, this 

er pos 

ater a 

t of i 

e and 

incre 
xygena 
s . 



the following probable effects. One beneficial 
the diversion vould be the dilution of toxic sub- 
the vater v.'hich v.-ould possiblv increase algal nro- 
nd thus algal biomass. This would necessarily 

other trophic levels which are dependent on the 
ood and oxvgen production in the v;ater. However, 
(1974: 1) reported that hcav\' metals (which are 
toxic to algae) in the Illinois T?:ver were n^t 
limiting factor, at least in the scope of his 
benefit for algal growth would likely be irdnimal 
sible beneficial effect would be the increase in 
reas along the length of the Illinois Piver as a 
ncreased depth. If backwater areas were to in- 
turbiditv decreased, then a likelv result would 
ase in algal production v;hich would be beneficial 
tion of the water and increases in food for con- 



If the result of the increased diversion were to d 
the turbidity in the waterway, the increased light avai 
ability would be beneficial to the phvtoplankton by all 
ing more photosynthesis at greater depths throughout th 
waterway. This effect would also be beneficial to the 
periphytor. growing along the banks of the waterway bv a 
ing the periphyton to colonize at greater depths than o 
presently. The advantage gained by the phvtoplankton w 
be somewhat less than that of the periphyton due to the 
nature of phvtoplankton. Since phy toplankton are suspe 
in the water, the increased current due to increased di 
would carry them down the river system more quickly thu 
allowing less time for growth and reproduction. The ve 
increase would also allow the phytoplankton less time i 
to utilize nutrients and provide oxvgen needed by decom 
bacteria for breakdown of any wastes present. Also, si 
the lowest densities of phytoplankton observed in the w 
way in 1978 were near the inlets of Lake Michigan water 
diverted waters from the lake at those locations would 
ently increase the dilution of these populations and th 
of the area affected. Based on predictions by the Illi 
Water Survey, if turbidity caused bv inorganic substanc 
reduced proportionally to various chemicals mentioned b 
the increased diversion v.-ould only slightly increase th 
euphotic zone (zone of productive photosynthesis) in th 
river and would not likely effect the middle and lower 
of the Illinois River. When these results are weighed 
the negative effects of increased current velocity and 
of phytoplankton with Lake ^'ichigan phvtoplankton, the 
positive effect of increased light penetration would be 
minimal . 



ecreasp 
1- 
ow- 
e 

llow- 
ccurs 
ould 

nded 

version 

s 

locitv 

n which 

posing 

nee 

ater- 

> 

appar- 

e size 

nois 

es were 

y them, 

e 

e upper 

section? 

against 

dilution 

overall 



Algae 16-29 



If on the other hand increased current pro]onped 
settling or increased the amount of suspended particles in 
the vater, this increase in turbiditv would reduce the euphotic 
zone depth. The decrease in available light would be detri- 
mental for algal growth, which mav be nost limited bv tur- 
bidity in the Illinois River already (Wang, IP?-!: 1). If 
the increase in depth allows further use of the Illinois 
River bv barge traffic in the summer months, these activities 
could be detrimental to algal growth as a result of continu- 
ous high turbiditv during those months (^'ills, Starrett , and 
Bellrose, 1966: 7). 

Nutrient levels in the Illinois River are enough to 
support considerable algal growth. In fact, phosphorus 
concentrations in the Illinois River are rcnortedlv among the 
highest in the U.S. Public Health Service nationwide stream 
monitoring svstem (V.'ang, 1974: 1). Wang (1974: 1) also stated 
that am^ple amounts of nitrogen are present in the Illinois 
River to support extensive algal growth but extensive growths 
are not frequently observed and the river appears barren. 
Forbes and Richardson (1919: 145) also mentioned that con- 
siderable amounts of plant nutrients flowed from the Illinois 
River unused bv the algae. The effects of increased diversion 
on the nutrient concentrations in the Illinois River would 
be to decrease concentrations of those chemicals but thev 
would most lilcely still be present in quantities sufficient 
for considerable algal growth. This idea is supported by 
predictions of nitrate and phosphorus concentrations after 
dilution by increased diversion (Illinois State Water Survey, 
(1^80). these nutrients would evidently be diluted most in 
the Chicago area but sufficient amounts for extensive algal 
growth would still be present along the entire waterway. 

The effect of increased diversion on temperature could 
be of importance to algal growth and production. Increased 
diversion in the summer would probably decrease temperatures 
slightly in the upper reaches of the river which would as a 
result decrease biological activity. This would include not 
only algal production, but also bacterial breakdown of sewage. 
The effects of winter diversion would probably be minimal 
since biological activity in the waterway would be low already. 
The overall effects of temperature change would probably be 
minimal for the majority of the waterway. 

Since it was noted that certain phvtoplankton and 
periphyton taxa were found in greatest numbers or sometimes 
exclusively at sampling locations nearest Lake ^'ichigan, 
another possible effect of increased diversion would be to 



Algae 16-30 



increase the success of these species at greater distances 
from the lake. It should be noted that although the algal 
species found onlv at locations nearest the lake were con- 
sidered to be migrants from Lake ^'ichigan, some of these 
taxa including Tabe llaria fe nestrata , Cvclote lla c omta , Cvclo - 
tel la kutzingiana , C vclotella ocellata , T^ragi laria crotonensis , 
Asterionell a formosa , and Aster i onella formosa v . graci 1 lima 
have been found at other locations in the state and are not 
necessarily limited in distribution to Lake >'ichigan and the 
adi acent areas . 



PPOBABLE ADVERSE EFFECTS OF INCREASED LAKE MICHICAN DIVERSION 
ON THE ALHAE IN THE WATERWAY WHICH CANNOT BE AVOIDED 



The adverse effects of increased diversion on algal 
communities along the waterway would include dilution of 
existing phytoplankton populations with more sparsely popu- 
lated Lake Michigan waters; increased current velocity would 
reduce time for algal absorption of nutrients and production of 
biomass for consumption by consumers and of oxygen for micro- 
bial breakdown of organic wastes in the system. Also, the 
possible delay in settling of suspended silt could reduce 
the depth of phyotosynthetic activity. These effects would 
be most dramatic during low flow summer months when most 
of the increased diversion is expected. 



17-1 



CHAPTER 17 : ZOOPLANKTON 

Stephen '.Vaite 
INTRODUCTION 

The objectives of this chapter are: (1) to describe 
and compare the historical and current status of zooplankton 
in the Illinois Waterway, (2) to review the basic 
hydrologic and physicochemical parameters that probably af- 
fect riverine zooplankters in the I llinois Waterway , and (3) 
to predict the impact of proposed increases of Lake Michi- 
gan diversion waters on existing zooplankton populations. 

HISTORICAL PERSPECTIVE 

Pre-1900 

Hempel (1902) and Kofoid (1903) investigated various 
constituents of the Illinois River zooplankton from 1894 
through 1899. Their data indicated that the condition of 
the river during that period was very favorable for the re- 
production of pelagic (deep water) as well as littoral (shal- 
low water) species; the slow-moving stream contained long 
sluggish pools and was only moderately polluted. The lower 
half of the river was characterized by a large number of lakes 
atid backwaters that provided for the expansion of flood waters 
and contributed large populations of aquatic fauna and flora 
to the main channel. Kofoid (1905:233) summarized his in- 
vestigation of the period prior to 1900 by stating: 

"The production of plankton falls to its 
minimum, as a rule, in January and February, and 
reaches its maximum in April, May, and June. 
Floods, of course, dilute it, but, on the other 
hand, a season of general high water increases its 
total quantity, and a season of general low water 
decreases it. Light and heat favor its develop- 
ment, and it is consequently more abundant, other 
things being equal, in a season during which 
clear and warm weather preponderates than in a 
cold and cloudy one. The freezing of the river 
does not seriously affect it, unless the ice- 
sheet continues until the water becomes foul 
with the gases of decay. The addition of sewage 
to the river greatly increases the productivity 
of this minute life by increasing the supply of 
available food, although an excessive amount of 



Zooplankton 17-2 

sewage may render the water too foul for it at 
the point of discharge." 

Post-1900 

The 1900 opening of the Chicago Sanitary and Ship Canal 
caused a radical change in the upper river by greatly in- 
creasing the average depth and flow of its waters and length- 
ening the period and range of its overflows. Although the 
amount of sewage was greatly increased, the concentration 
was actually less than before .1900 (Forbes and Richardson, 
1919:143). It was expected that municipal sev/age and stockyard 
wastes would decompose naturally within a short distance, 
but the growth of cities within the watershed overburdened 
the river and sent pollution-laden waters further downstream. 

Data collected by Forbes and Richardson (1919:146) in 
1909-1910 showed that increased nutrient levels resulting 
from sewage wastes caused the total plankton passing Havana 
to surpass that of the 1890 's by 69 percent, while the num- 
ber of plankters in the backwater regions exceeded that of 
the earlier period by 218 percent. It was emphasized that 
increased production may have been lost downstream as a re- 
sult of extensive reclamation of bottomland regions. The 
construction of levees increased the water velocity in the 
main channel and reduced the size of backwaters formerly 
available for "digestion" of organic wastes and subsequent 
growth of fish-food organisms. The importance of those back- 
water areas for plankton production was recognized earlier 
by Kofoid (1905:223) : 

"... the stagnant and relatively permanent waters 
of the shallow lakes bear a more abundant plankton 
than the waters of flowing streams, and the out- 
flow from such areas hence enriches the plankton 
of the river." 

and Forbes and Richardson (1919:147): 

"If the running water were left wholly to 
itself, the river would speedily empty itself of 
plankton; to maintain the floating population 
there must be a constant source of supply outside 
the waters involved in the downward movement. 
Such a supply can be found only in places where 
aquatic organisr;s are virtually stationary, or 
from which, to say the least, they do not escape 
until they have themselves begun to multiply, and 
in which, consequently, they will leave fertile 
descendents behind thera. Such places of possible 
continuous origin of the plankton organisms are 



Zooplankton 



17-3 



weedy waters along shore, sluggish shoals, eddies, 
bays, sloughs, open backwaters of the bottom-lands, 
and lakes connecting with the stream. The river 
plankton originates in the mere overflow of the 
stationary population in such breeding places, 
and the reduction of these sources of supply must 
have its appropriate effect on the river product. 
Hence, the plankton productivity of the stream 
does not depend primarily on the richness and ex- 
tent of its own flowing waters, but on those of its 
subsidiary breeding grounds. . ." 

While the studies of Hempel, Kofoid, Forbes and Richard- 
son established an extensive and detailed data base during 
the turn of the century when major changes were occurring 
within the Illinois River, none of the studies examined the 
waterway in its entirety. However, in 1928-1930, an expert 
planktologist with the U.S. Public Health Service (Purdy 
1930) surveyed representative portions of the river down- 
stream of Chicago and correlated his biological data with 
various physicochemical parameters. Table 17-1 summarizes the 
results of Purdy's study with those of Forbes and Richardson. 
Although conditions in the Des Plaines River at Lockport 
appeared to improve in terms of zooplankton in Purdy's study, 
the outlook for those organisms further downstream (Morris 
to La Salle) was not promising. Zooplankters that were some- 
what numerous in the earlier study became relatively uncommon 
10 years later. Both studies did show a transitional zone 
just above Peoria where waters appeared to become less pol- 
luted. 

Unfortunately, no major studies of zooplankton were con- 
ducted in the Illinois River for a 40-year period following 
Purdy's (1930) publication. Although few changes occurred 
in the physical hydrography during that period, one alteration 
that probably affected the zooplankton was the construction 
of major navigation dams. 

Beginning in the 1970's, various utility companies and 
other corporations contracted for studies regarding the en- 
vironmental effect of certain perturbations that might later 
be deemed harmful. For example, Wapora, Inc. (1974) sampled 
the Illinois River in 1973-1974 at Hennepin, Havana, and 
Meredosia to investigate downstream effects caused by once- 
through cooling waters of electric utility plants. While no 
mention was made of river conditions, population trends sim- 
ilar to earlier works were noticed, e.g., total population 
abundance tended to increase in a downstream direction, roti- 
fers were the dominant organisms at all stations, and the 
percentage of copepods and cladocerans tended to increase 
in the downstream stations. 



Zooplanlcton 



17-4 





>s 


-o 




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1— 1 


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c 


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c 


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oct: 


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c 


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in 


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a»- 


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4-> UU 


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>. 


CX) 


CO 






^t 


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0> 


C 


> 


o 


•H 


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cx: 


♦J 




•H 


V) 


T) 


•H 


c 


o 


o 


c 


O 


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r-^ 


»-i f-t 


0) 


t— 1 


> 




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(U 


^-. j= 




+-> 


tH 




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c 


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4_i+j+jaiE'+-'i>i'' •'"' 




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rH 1— 1 3 -H 0<= re •!-> iH C 




iH t-i CO 


c ■«■ !> re o o 




o x; u -H 


r: -H rH x: 3 o 




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•H >-c £ 


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o oj t- DO re ■M 




3 -H re 


DC O C 3 




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X re iH -H T3 




•H re o ^ :s c 0) 


o 


C1>DT^'^3<D':^°00^-| 


^H 


•hihj: c c >vox:-h co 


Oi 


Z OH 


re 


•-< CO 00 (ft +J D-'H 



+-> 


0) 


p- 


E 


o 


CO 


w 


CO 



o 


c 




o 


^> 


4-) 


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c 


L) 


re 


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re 


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Zooplankton 



17-5 



T3 , 







c 






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_c 




■(-> E 03 


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0) T-l 




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^^ 1— 1 




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re 




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CO x: 




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-t-i 




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O ••-' o c 


J 3 






T3 T3 




DO 3 03 


C O 




03 • (U 


03 -M 




■M CO 3 U 


D 




C C O 03 


tr, 1— 1 




O -H T-H +J 


• H 1— I 




(J !-i t/l 


S-. o 




^ 3 C D 


^ a 




o -zi O u 


o 




CL, -MO 


S i-i 




1/1 ^ o 


cu 


>-i 


x; E c !-H 


+-J ■!-> 


O 


DO S-i 03 U 


< 03 -O 


•tH O 1-H -H 


^ 3 


o 


— >+H CI. E 



1 t/1 0) 




0) 


• H (-1 1— ( 




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to (1) L) 




(- c 


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oj 03 03 O 




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a> r-l J- 


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to oi OJ t/) 


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f- t3 in O -r-l 


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c 


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p. 

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Zooplankton 



17-6 



f-i 




C (i> 


*-> 




1—1 




D 




O D 


m re 




M 


to 


• - tn 




4-> -O 


(U X 




C 




0) 




^ 


t^i •(J "O 


Ul 


•H 


to 


dJ o 




C " 


re c • 


C 


1/) I-i -t3 


E 


^- c 




re Oi 


D LO re ID 


re 


•rH QJ a> 


(h 


M 




1—1 >- 


(- E ■•-> 


a; 


P C ^-i 


o 


(i> x: 




ex a; 


u trt re c 


u 


D< re <L» 144 


tJ •t-' 




x; 


C 'H -H <D 


re 


i-i QJ XI 




• rH 




1— 1 


•H C 1- 3 


+-> 


3 -1 E 


4-> 


'H 3 




re 1/1 


re o — 1 


</> 


(/) U 3 


c 


t-H 




■»-> ^- 


a> DC a> '4-1 


3 


C 


re 


re i- 




O 3 


DO ^^ a, '4-4 


^-1 


C W 4-1 


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E r; 




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J- o o 


u 


•r4 re 3 


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ID O 




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ro E 




o 


—4 


r-H 




*-> c 


1-1 c o o -o 


4-* U-. 


O 


O U 




to 


o *-• c* c 


C li t/) 


+-> 


■fj 




Oj c 


o -H VH re 


re 


OJ OJ E 


1 


t/5 


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v^ o 


*->*-> 3 




c/1 X 5-1 


c 


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re -^ 


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U) 


DEO 


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fl> 3 


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1-4 


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c '4-( (L> a> 


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0) -H re 


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(X ? '^-i H Dh 


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3X3 


CX+J 





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I— 1 


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t/i If) 


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u. 


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c 


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5-c 


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<-l u u 



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CO 
T3 






E 
O 

u 



t3 

d' 
-C 

3 
I— ( 

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c 
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c 


t 


o 


u 


4-1 


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^ 


1— 1 4-1 


n; 


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1—1 


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o 


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c 
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4-> 

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1-4 
(X 

o 

o 



Zooplankton 17-7 

Colbert et al. (1975) provided an aquatic inventory and 
assessment of the aquatic biota as affected by the operation 
and maintenance of the 9-foot channel in pools 24, 25, and 
26 of the Mississippi River and the lower 80 miles of the 
Illinois River. Much of this study dealt with comparisons 
of the biota of these two river systems; however, little 
was mentioned regarding the actual stream condition in 
terms of its significance in the role of providing a viable 
habitat for zooplankton. While the data showed no indica- 
tions of stress resulting from sewage or other organic de- 
composition, the below normal densities of zooplankters in 
some side channel areas (river mile 2.5 to 81) may have been 
the result of heavy metals accumulation. Rotifers were 
abundant everywhere and the presence of copepods in the lower 
reaches of the Illinois River was probably indicative of 
relatively unpolluted waters. 

STATUS OF EXISTING ZOOPLANKTON POPULATIONS 

This section summarizes a recent investigation of zoo- 
plankton communities at 12 sampling locations in the Illinois 
V.'aterwav and one location in pool 26 of the Mississippi 
River. ' It should be noted, however, that the resultant data 
reflect a relatively short sampling period (July, August, 
and September 1978), and, thus, the results and conclusions 
were necessarily limited to generalized discussions. 

The status of existing zooplankton populations was 
determined with the aid of specific analyses of (1) species 
composition and distribution, (2) species diversity, (5) 
the abundance of major groups, (4) similarities of sampling 
stations, and (5) relative comparison of estimated zooplank- 
ton biomass. 

Description of Sampling Areas 

Zooplankton samples, as well as phytoplankton , peri- 
phyton, and other ancillary measurements, were collected 
from 12 locations in the Illinois Watens'av and one 
station in pool 26 of the Mississippi River. Those sites 
were selected on the basis of (1) providing a convenient 
access to the waterway, (2) reducing the chances of vandal- 
ism to in situ samplers, and (3) collecting one or more 
samples"Trom each navigation pool. Table 17-2 gives station 
name, location (in river miles from mouth), and a brief 
description of the hydrological conditions at each station. 

Four stations were selected to represent surface waters 
in Greater Chicago, i.e., the North Branch of the Chicago 
River, the Chicago River, the Cal-Sag Channel, and the 



Zooplankton 



17-8 



o 


. 




•l-( 


X 




*-> 


t— I 




CO 


3 




■(-> 


•-5 




LO 






oo 


^ 




c 


d) 




•l-t 


> 




t— 1 


•r-l 




txoi 




E 






« 


•H 




en 






c 


• ^ 




o 


tn 




4-> 


t/) 




^ 


•H 




c 


Wi 




« 


!/) 




f— I 


•r^ 




CI. 


2 




o 






o 


<u 




tNJ 


*-> 




o 


o 




t/> 






c 


o 




o 


(Nl 




■H 






+J 


i-H 




C5- 


o 




•H 


o 




ll 


0. 




u 




00 


tfl 


TD 


r~- 


(U 


ca> 


Q 


re 


'- 


T3 


X w 


C 


re 


<b 


re 


2X1 




>-. 


E 


re 


o 


<u 


<-> 


^ 


■(-1 


« 


re 


c- 


Q S 


QJ 






W 


i-H 


(/) 




rt 


•iH 


T3 


u 


o 


C 


•H 


c 


re 


M 


• rH 




O 


rH 


•, 


1— 1 


t— 1 


4-> 


o 


I-H 


tn 


c 




3 


E 


<U 


W) 




x; 


D 


J 


•4-» 


< 










X 




1 re 




1 




» 


^ 








ro 




E •'1 M 


C 


^ 


o 


D, 


re 






+-< 


•(-> o 




CO X: -rH • 


.rH 1—1 • 


(U 


4-> 


3 


<u 






re 


O GC 




o u X ■M 


c; *-> 


> 


<u 


U) 


c 






o 


o re 




Vh o c 


(U C D, 




^ 


(D C 








JO 


■(-J 4-> 


c 


•t-' tC-H O 


f- c a» 


p. 


u 


X re 


■M 






o 


(U 01 


o 


(/I c s >— ' 


o re CO 


o 


c 


*-> f-< 


c 






c/l 


TD 


• iH 


C — 1 3 


j= j: 


4-> ' 


o 


o 


re 






D 


•ri 


4J 


S ^ O X) 


(rt u c 


t6 I-H 


o 


c wo 






O 


V) o 


u 


o re ^ J- 


.iH 


re • 




o o 


c • 




c/^ 


J= 


re o 


o 


13 (-. re 3 


E - 


E C Oj 


E 


T3 


3 DC 




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Zooplankton 17-11 

Sanitary-Ship Canal (Fig. 16-1). Other stations in this region 
included Lockport Lock and Dam (also on the Sanitary-Ship Canal) 
and the Brandon Road Lock on the Des Plaincs River . The 
Dresden Island Lock and Dam marked the first sample location 
in the Illinois River proper (Fig. 16-2) and all but two of the 
remaining stations downstream were located at navigation locks. 
The Illinois Waterway station closest to its mouth was the Kamps- 
ville ferry. Since samplers were vandalized at that location, 
subsequent visits for the remaining two months were made at 
^1ichael's Landing, a less-used public access 4 miles downstream. 
Pool 26 of the Mississippi River was sampled at Royal Landing, 
virtually midway between locks 25 and 26. 

Methodology 

Triplicate samples of Illinois Waterway zooplankters were 
collected monthly in July, August, and September 1978 at 13 stations 
described in the preceding section. All samples were procured 
with a submersible filter-pump apparatus (Waite and O'Grady, 
manuscript accepted) that was deployed either from shore or 
from the walls of the navigation locks. Water from the upper 
2 m was sampled for 2-minute intervals at a rate of 40 liters/ 
minute. Total volumes of river water filtered per three 
replicate samples at each sampling station never exceeded 250 
liters. After the concentrated samples were removed from the 
sampler, the zooplankters were fixed and preserved in a S% formalin- 
501i alcohol solution tinted with rose bengal. 

In the laboratory, organisms were enumerated and identified 
with a stereo dissecting microscope (lOx to 80x) and 
a binocular compound light microscope (40x to 600x) . Keys 
and other literature used in the taxonomic analysis included 
Ahlstrom (1940, 1943), Pennak (1953), Brooks (1957, 1959), 
Edmondson (1959), Wilson and Yeatman (1959), Wilson (1959), 
Yeatman (1959), Goulden (1968), Smirnov (1974), and Chengalath 
(1977). The standing crop of zooplankton and net phytoplankton 
biomass was ascertained by filtering, drying, and ashing all 
samples (A,PHA et al., 14th ed.: 1035), with the residues 
reported in milligrams of dry and ash- free weight per cubic 
meter of river water. Analyses of the community structure of 
zooplankton were aided by utilization of a species diversity 
index (Wilhm and Dorris, 1968) and a cluster analysis (Church, 
personal com.munication) . 

Results 

Composition and Distribution of Zooplankton Species 

The predominant forms of zooplankton collected during 
this investigation included 41 taxa of rotifers and 44 



17-12 
Zooplankton 

microcrustaceans CAppendix t^, Table F- 1) . Other forms infrequently col- 
lected were protozoans, ichthyoplankters (larval fish), and 
meroplankters (larval insects, worms, Hydra ) , which are only 
part-time constituents of the zooplankton. Several benthic 
forms, such as amphipods (sideswimmers) , gastropods (snails), 
and Hydracarina (water mites) were common in samples taken 
after the passage of barges. 

Rotifera. The most common and widely distributed 
rotifers in the Illinois River waterway were those belonging 
to the family Brachionidae . Although many species of the genus 
Brachionus did not occur in the North Branch, Chicago Lock, 
or the Sanitary-Ship Canal, they were a dominant form at 
virtually all other downstream stations. Since two species 
of the genus Keratella , K. cochlearis and K_^ quadrata , are 
considered by Arora [T96^ to be indicators of eutrophic 
conditions, their presence in the Illinois waterway at 
Chicago may reflect the eutrophication (to whatever degree) 
of those waters. Prins and Davis (1966:8) suggested that 
many forms of organic pollution may resemble naturally eu- 
trophic water? and thus certain species (like Keratella ) may 
exist in a polluted waterway. 

Although several rotifers were observed only in the Chi- 
cago area stations, their presence in these regions was probably not due to 
their tolerance of polluted waters but rather as a result 
of being swept into the waterway from Lake Michigan and then 
dying. Euclanis sp., Trichotria tetractis , and Mono sty la 
quadridentata were collected only at the North Branch while ' 
Notholca acuminata and Mytil ina ventral is were each found, 
respectively, at the Chicago Lock and the Cal-Sag Channel. 
While Trichotria porcellus was collected at both the North 
Branch and the Sanitary-Ship Canal, Ploesma sp. was collect- 
ed at those stations plus the Chicago Lock. Trochosphaera 
solstialis seemed entirely misplaced by appearing only at 
the two opposite ends of the waterway, the North Branch and 
Michaels Landing. Since most of these species have been col- 
lected in various Lake Michigan studies (Duffy and Listan, 
1978:46-49; Stomberger, 1974:128-134), they apparently were 
not permanent constituents of the river community. 

Cladocera . Bosmina longirostris was the only clado- 
ceran species collected at all stations in the Illinois water- 
way. Moi na micrura ranked second to Bosmina in overall 
abundance^^ut its distribution was generally restricted to 
the stations below river mile 308. The remaining species 
were relatively uncommon and occurred only sporadically at 
several stations. While the occurrence of some was restrict- 
ed to the upper waterway ( Polyphemus pediculus , Eurycercus 
lamellatus , Chydorus gl obosus , and ~Rlonella acutirostris ) 7 
Alona rectirostris was found only in the middle to lower 



Zooplankton 17-13 

regions, and Leptodora kindtii , the largest cladoceran, was 
collected only in pool 26 of the Mississippi River. 

Copepoda . As in many lakes and reservoirs (Pennak, 
1978:59 6), tHe copepod fauna in the Illinois River was domi- 
nated by one calanoid and one cyclopoid species. The cala- 
noid, Diaptomus sic iloides , was not collected at the North 
Branch nor at the Chicago Lock, but was extremely prevalent 
in the remaining stations. All but one of the remaining 
calanoids, however, occurred exclusively at the North Branch 
and the Chicago Lock. 

The cyclopoid, C yclops vernalis , was extremely common 
and abundant at all sampling stations. Eucylops speratus 
was collected only at Lockport and Brandon Road, while E . 
agilis and C_^ bicuspidatus thomasi were limited primarily 
to the Starved Rock, Marseilles, and Dresden Island pools. 
C. vernalis and Macrocyclops albidus were the only two cyclo- 
poid species reported from pool 26. 

Abundance of Major Groups of Zooplankton 

Rotifera. The most conspicuous characteristic of the 
abundance data (Appendix^, Table ^-2) was the high degree of variability 
of various constituents throughout the waterway. With two 
exceptions (the North Branch and the Chicago Lock) , organ- 
ism density tended to increase in a downstream direction. 
This trend was especially true with rotifers- their numbers 
were relatively high (10,000 to 64,000 per m^) at stations 
in the Chicago area, followed by a slight decrease above 
the confluence of the Kankakee with the Des Plaines River, 
and then a substantial rise below Dresden Island with the 
greatest densities (100,000 to 300,000 plus per m-^) between 
Marseilles and Kampsville (or Michaels Landing). One other 
trend of interest was the near similarity of rotifer densi- 
ties in September at four consecutive stations in the water- 
way. There was a difference of only 613 rotifers per m-^ in 
the populations at the Cal-Sag Canal and the three lock and 
dam facilities downstream (Lockport, Brandon Road, and 
Dresden Island). The density of rotifers in pool 26 of the 
Mississippi River was roughly one-half of the lowest values 
recorded in the Illinois waterway. While the abundance of 
rotifers during this study equalled only 20 to 25 % of 
the total abundance reported by Kofoid (Sparks, 1979:19), 
it was similar to the more contemporary data of Williams 
(1966:84) at Peoria and Colbert (1975) for the lower 80 miles 
The low rotifer densities of the upper waterway may have 
been the result of their intolerance to various forms of 
toxic effluents. Williams' (1966:88-90) comparisons of 
rotifer and phytoplankton data revealed that, in most rivers, 
the Rotifera were generally associated with waters of rela- 
tively high clarity, which, in turn, supported abundant 
populations of phytoplankton. 



17-14 
Zooplankton 

Cladocera. As is typical for most river systems, the 
cladocerans were considerably less dense than the Rotifera, 
although their numbers were nearly the same as those re- 
ported by Kofoid (Sparks, 1979:19) and Colbert (1975). It 
is interesting to note that cladoceran density was very low 
in July, ranging from to 13,720 individuals per m^. But 
in August and September when Dresden, Marseilles, and 
Starved Rock locks were closed to river traffic, cladoceran 
abundance increased dramatically with the abundance of the 
six stations below Brandon Road averaging 19,980 and 40,161 
individuals per m^ for those two months, respectively. This 
increase rnay have been related to changes in the physical 
conditions of impoundment that occurred when the barge 
traffic was terminated. Thus, the cladocerans, which 
normally have high densities in reservoirs, were attaining 
atypically high densities in the Illinois Waterway due to de- 
creases in water velocity, turbulence, and turbidity. The 
abundance of cladocerans in pool 26 of the Mississippi River 
was similar to that of other Illinois River stations in 
July; in September, however, it barely equalled the lowest 
value of the entire Illinois Waterway. 

Copepoda . Although the Copepoda constituted a very in- 
significant fraction of total zooplankton in Kofoid's study 
(Sparks, 1979:19), these animals were of major importance 
in this investigation, comprising between 10 and 501 of the 
total zooplankton numbers (Appendix F.Table F- 2). Kaujilii and cope- 
podida (larval life history stages) were present in all 
collections and outnumbered the adults by two- to five-fold. 
Following the trends of other zooplankton groups, the density 
of copepods was extremely variable, ranging in September 
from 100 mature individuals per m^ at the Chicago Lock to 
247,000 larval forms per m^ at Marseilles. 

The means of total numbers at each station were also 
calculated for each month. In July, the mean of all Illinois 
River stations was 80,663 organisms per m^ while the means 
for August (144,136) and September (128,981) were 50 to 
751 greater. These values were still lower than Kofoid's 
total, but were similar to the results of Colbert (1975). 

Comparison of Species Numbers 

During the course of the present investigation, I 
observed that the numbers of species had sharply declined 
since the turn of the century. In Table 17-3 the numbers of 
species collected in this study are compared with those of 
Hempel (1902), Kofoid (1903), and Colbert (1975). In the 
vicinity of, Havana (river mile 120-125), Kofoid reported 
29 taxa o£ rotifers, five cladocerans, and seven copepods. 
While the 1978 study did not sample the specific Havana 
area, combined data from Peoria Lock (river mile 158) and 



Zooplankton 



17-15 



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17-16 



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Zooplankton 



17-17 



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Zooplankton 



17-1 



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17-19 



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17-20 



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[ooplankton 



17-21 



X X X X X 



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Zooplankton 



17-22 



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Zooplankton 



17-23 



13 
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Zooplankton 17-24 

La Grange Lock (river mile 80) yielded only 11 taxa of roti- 
fers, five cladocerans, and two copepods. Combining Hempel's 
(1902) data vsith that of Kofoid's for all of their sampling 
stations (river mile 27-208) yielded 100 taxa of rotifers, 
seven cladoceran species, and eight copepod species. In 
comparison, the 1978 study, which sampled between river mile 
27 and 351.5, yielded 41 taxa of rotifers, 28 cladocerans, 
and 16 copepods. Although the decline in rotifers can be 
explained in part by historical changes in rotiferan taxon- 
omy, the increases of cladocerans and copepods were probably 
due to sampling waters that were immediately upstream of 
the locks and dams. Those areas appeared to be more lake- 
like, having populations of microcrustaceans similar to 
central Illinois reservoirs (Waite, unpublished data). The 
1978 data taken from river miles 27 to 80 were also compared 
to that of Colbert (1975) who sampled the lower 80 miles for 
studies on the Mississippi River. Though differences were 
slight in this comparison, they may be the result of a more 
proficient sampling regime in the 1978 study. 

A historical summary of all zooplankton taxa collected 
in five major plankton investigations is given in Table 17-4, 
Although a total of 127 taxa of rotifers have been identi- 
fied, more than 501 (70 taxa) were reported only by Hempel 
(1902) and Kofoid (1903). It is suspected that, in addition 
to changes in taxonomy, alterations of river habitats and 
the deterioration of water quality since the turn of the 
century have had a synergistic effect on the rotifers of the 
Illinois River. 

Of the species collected in the 1978 study, 11 rotifers, 
22 cladocerans, and nine copepods were apparently new his- 
torical records for the Illinois River system. It is pos- 
sible that others might be collected if a year-around samp- 
ling regime would be initiated. 

Cluster Analysis 

I hypothesized that changes in species composi- 
tion of zooplankton from the headwaters to the mouth of the 
Illinois River would define distinct geographical zones in 
the Illinois waterway. For example, poor water quality in 
the Chicago portion of the waterway might result in kinds 
and numbers of species unlike those of the navigation pools 
further downstream. Zooplankton data from 12 sampling sta- 
tions (the analysis did not include pool 26 of the Missis- 
sippi River) were subjected to a computerized cluster 
analysis based on matrices of modified Jaccard's coefficients 
(Church, personal communication). The dendograms in Figs. 17-1, 
17-2, arid 17-3 display, in a hierarchial fashion, the relative 
strengths of similarity of the sample stations. The index 
utilizes both the presence and absence of species, and the 



Zooplankton 



17-25 






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17-27 



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Zooplankton 



numbers of individual organisms. On an index scale, verti- 
cal bars are connected between two items (in this case, 
sampling stations) to form a cluster and the position of 
the bar relative to the horizontal scale indicates the 
level of similarity. The scale is inverted so that diminish- 
ing levels of similarity are longer horizontal lines on the 
graph. A separate analysis was conducted for each month so 
that zonations of the waterway based on zooplankton commun- 
ity structure could be detected before and nossiblv during 
lock shutdowns at Dresden, Marseilles, and Starved Rock. 

Species composition of zooplankton in July 1978 was 
highly diversified vithin and between the various regions 
of the Illinois waterway. The degree of cluster separation 
revealed that the waterway contained several distinguishable 
geographic zones during normal flow. In Fig. 17-1 those 
zones are specifically delineated by clusters labelled A, 
B, C, and D. In July, the groups contained two or more sta- 
tions that were usually immediately upstream or downstream 
of each other, as in cluster B of the lower river (Starved 
Rock, Peoria, La Grange, and Michaels Landing). However, 
note the absence of Dresden Island from the cluster con- 
taining Lockport, Brandon Road, and Marseilles; its zoo- 
plankton assemblage was more similar to that of the Cal-Sag 
Canal. The least similar couplet contained the Chicago 
River Lock and the Sanitary-Ship Canal at Willow Springs. 
The North Branch appeared to be the most unique or dissim.ilar 
station as it clustered with the remaining 11 stations at 
a relatively low point on the scale (approximately 0.350). 

Higher similarities and greater separation were the 
trends for August and September. Just as the lower stations 
as a whole were greatly dissimilar to the remaining water- 
way in July (Fig, 17-2), the upper regions were completely 
segregated in the August sample. In the middle region, 
Marseilles, Starved Rock and Peoria were very similar and 
were separated by only a short distance on the scale from 
cluster B containing La Grange, Michaels Landing, and Dresden. 
The close proximity of clusters A, B, and C in August. suggests 
a high degree of basic similarity of stations in the lower 
and middle regions . 

In September, conditions resulting fromi the closed 
locks, heavy rains, and subsequent flooding in the Chicago 
area, probably played a significant role in homogenizing 
the upper and middle regions of the Waterway (Fig. 17-3). 
In fact, there were only three major clusters, two of 
which (A and B) contained stations in the upper 501 of the 



Zooplankton 17-29 



vaterway. Cluster C had the smallest number of stations, 
but it represented the lover 160 miles, where the river 
exists in its most natural form. 

It is probable that during normal flow there are at 
least three distinguishable regions of the waterv/ay based 
on similarity patterns of zooplankton communities. At certain 
times (as shown in the August dendogram) the diversion of 
Lake Michigan waters into the Chicago River and its North 
Branch yields a similar zooplankton community structure for 
most waters in the Chicago region. Flooding, i.e., higher 
water levels and increased discharge, did little to change 
the number of basic similarities, but generally under those 
conditions the zooplankton constituancy appeared to be more 
homogeneous in the upper to middle regions, as evidenced by 
the clustering of non- consecutive stations. 

Species Diversity 

IvTiile the use of species diversity indices in aquatic 
biology has been limited primarily to evaluations of stressed 
and unstressed benthic assemblages, the methodology was use- 
ful for comparing the relative condition of zooplankton 
populations in the Illinois waterway. The primary purpose 
of this analysis was to use a diversity index (Kilhm and 
Dorris 1968) to define specific regions of the river that 
were stressful for their zooplankton constituents. For ex- 
ample, it was expected that zooplankton diversity of sta- 
tions in the Chicago portion of the waterway would be rela- 
tively low due to poor water quality conditions reported 
for that area (U.S. Public Health, 1961 52-67). 

Compared to various Illinois lakes (Waite, unpublished 
data) where zooplankton diversity values generally ranged 
from 0.5 to 4.0, the range of values in the Illinois water- 
way was considerably narrower, i.e., 1.4 to 3.4 (Table 17-S). 
While the data were variable at the Chicago stations (aoove 
river mile 300) during the collecting periods, diversity in 
general was much higher than expected. In fact, there was 
no evidence of a significant difference (0.05 level) be- 
tween the overall mean of those stations plus Lockport and 
Brandon Road with the mean of the five stations farthest 
downstream. Thus, it appeared that the water quality in 
Chicago surpassed that level which is minimally supportive 
of most riverine zooplankters . 

An interesting trend consistent for the three months was 
the decrease in diversity at Dresden Island. In July and 
September, the decline began at Lockport, whereas in August 
diversity increased at Brandon Road before declining to one of 



17-30 



Table 17-5. Specie? diversity values of zooplankton in 
the Illinois River and Pool 26 of the Mis- 
sissippi River, July, August, and Septem- 
ber 1978. 



Location 






July 


Aug. 


Sept. 


Mean 


North Branch 






1.4 


3.2 




2.3 


Chicago Lock 






2.3 


2.7 


3.1 


2.7 


Willow Springs 






3.2 


2.6 


2.7 


2.8 


Cal-Sag 






2.6 


2.9 


3.0 


2.8 


Lockport 






3.1 


2.1 


2.5 


2.6 


Brandon Road 






2.8 


3.2 


2.1 


2.7 1 


Dresden 






2.0 


1.7 


1.4 


1.7 


Marseilles 






1.8 


3.4 


1.8 


2.3 


Starved Rock 






2.9 


2.2 


2.7 


2.6 


Peoria 






2.6 


2.8 


2.7 


2.7 


La Grange 






3.0 


3.0 


2.3 


2.8 


Kampsville-Mic 


haels 


Landing 


3.2 


2.8 


2.9 


3.0 


Royal Landing, 


Pool 


26 


3.0 




3.0 


3.0 


Monthly Mean 






2.5 


2.7 


2.2 





Zooplankton 



17-31 



the lowest levels of the study. Generally, diversity in- 
creased progressively in a downstream direction, with the 
highest consistent values at Kampsville-Michaels Landing 
station and at Royal Landing in the >?ississippi River. 



to a 

I su 

Plai 

cont 

cons 

the 

orga 

fold 

Sept 

thos 

five 

disc 

negl 

coll 

comp 

basi 

Kate 

lock 

Augu 

the 

for 



An an 
ccount 
ggest 
nes Ri 
ribute 
t ituen 
Illino 
nisms 

incre 
ember, 
e two 
-fold, 
barged 
igble 
ection 
ared t 
c tren 
rway w 

shiitd 
St and 
plankt 
that p 



alys 

for 
that 
ver 
d la 
ts o 
is R 
at B 
ase, 

rot 

Stat 

Mo 

fro 
s inc 

rev 
o th 
ds o 
ere 
owns 

Sep 
on , 
erio 



is o 
the 
the 
1.5 
rge 
f mo 
iver 
rand 
res 
ifer 
ions 
rtal 
m th 
e te 
eale 
e pr 
f zo 
simi 

at 
temb 
and 
d. 



f th 
low- 
Kan 
mile 
numb 
St r 
. A 
on R 
pect 
den 
, bu 
ity 
e Dr 
mper 
d vi 
ofil 
opla 
lar 
Dres 
er r 
thus 



e zooplankto 
diversity v 
kakee River 
s above the 
ers of drift 
iverine zoop 

comparison 
oad and Dres 
ively, for J 
sities were 
t the microc 
of organisms 
esden Power 
ature profil 
rtually no t 
es of upstre 
nkton specie 
for each of 
den, Marseil 
esulted in a 
coiTiplicated 



n ab 

alue 

(whi 

Dres 

ing 

lank 

of t 

den 

uly 

virt 

rust 

due 
Stat 
es t 
empe 
am s 
s di 
the 
les , 
typi 

the 



undance 
s observ 
ch joins 
den Lock 
rotifers 
ton comm 
he numbe 
showed a 
and Augu 
ually th 
acean fa 

to heat 
ion was 
aken at 
rature i 
tations . 
versity 
three mo 

and Sta 
cal m.eas 

interpr 



data was used 
ed at Dresden. 

the Des 
) may have 

(dominant 
unities) to 
rs of those 

two- and 20- 
st . In 

e same between 
una decreased 
ed effluents 
considered 
the time of 
ncreases 

In conclusion, 
in the Illinois 
nths. But the 
rved Rock in 
urements of 
etation of data 



Biomass 



The zooplankton and net phytoplankton contained in all 
samples collected for this investigation were processed for 
estimates of dry and ash-free (total volatile organic matter) 
biomass. While both categories of data are given in Table 17-6, 
the latter is preferred when comparisons of data involve 
mixed assemblages. It should be noted that, while the data 
are relative, they are purely estimates, as the magnitude of 
error increases with samples containing large amounts of silt, 
detritus, and net phytoplankton. 

The mean ash-free biomass for the tJiree-month period at 
each sampling location ranged from 90 to 965 mg/m-^ . The 
lowest value for July and September was at Dresden Island 
and, consequently, that station had the lowest overall mean 
biomass for the three months combined. The location of the 
highest biomass in each month followed an interesting trend- 
it was highest at Marseilles in July, at Starved Rock, in 
August, and likewise at Peoria for September, With the 
exception of the North Branch, the mean biomasses of stations 



17-32 



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Zooplankton 17-33 



above the confluence of the Kankakee and Des Plaines rivers 
were virtually the same. Downstream of Dresden Island, the 
mean biomass increased two- to five-fold (^!arseilles through 
Peoria), and then dropped sharply at the last two stations 
(La Grange and Kainpsvi 1 le-Michaels Landing). One reason for 
that trend was probably the contribution of a very large 
bloom of net phytoplankton in the Starved Rock pool during 
this investigation (see chapter on Phytoplankton, this report) . 
The concentration of phytoplankters was greatest at Starved 
Rock each month and the populations subsequently declined at 
downstream locations by one-half, two-thirds, and three- 
fourths in July, August, and September, respectively. Although 
the diversity of zooplankters was high in the lower reaches, 
the predominant group, rotifers, contributed a very small 
portion of the total biomass. Mean ash-free biomass in pool 
26 of the Mississippi was similar to the extreme lower region 
(river mile 27-32) of the Illinois River. 

The organic fraction of the plankton biomass was rela- 
tively constant throughout the waterway with monthly means of 
45.6, 47.9, and 42.4^o for July, August, and September, respec- 
tively. While the minimum and maximum values were 26 and 62b, 
the mean percentage of all three months for each location 
ranged from 38 to 531; exactly one-half of the values were 
between 40 and 501. The organic fraction in pool 26 was 
variable: 291 in July to 1001 in August. The three-month 
mean for this station was 581, which was higher than any of 
the three-month means in the Illinois River stations. 

Summary of Results 

Forty one taxa of rotifers and 44 microcrustaceans were 
the predominant zooplankters collected in the Illinois Water- 
way during July, August, and September 1978. Of those taxa, 
11 rotifers, 22 cladocerans, and nine copepods appeared to 
be new historical records. Primary causes of a more than 501 
reduction of rotifer species since the turn of the century 
are thought to be physical changes of the river environment 
and deterioration of water quality. 

Species of the family Brachionidae were the most common 
and widely distributed rotifers throughout the waterway. 
Commonly used as indicators of eutrophic conditions, Keratella 
cochlearis and K^ quadrata were the predominant forms in the 
Chicago area, while other genera ( Euclanis , Trichotria , 



Zooplankton 17-34 

Monostyla , My t i 1 i n a , Not ho lea , and Ploesma ) were probably 
vashed in fror.i Lake Michigan. 

Only one cladoceran, Bosr^ina longirostris , was collected 
at all saiTipling locations. Moina mi crura ranked second to 
Bosmina in overall abundance, but its distribution was gen- 
erally limited to sampling stations below river mile 308. 
The remaining species were uncommon and most were found 
above river mile 291. The largest cladoceran, Leptodora 
kindt J J , was not found in the waterway during this study . How- . 
ever, it was present in low densities in pool 26 of the 
Mississippi River. 

The copepod fauna of the rivet below river mile 308 
was similar to that of r.anv central Illinois reservoirs where 
one calanoid and one cyclopoid taxa were the dominant forms. 
A majority of the calanoid species collected during this 
study were found exclusively at the North Branch and Chicago 
Lock stations, indicating that the community structure in 
those areas was related to the infusion of Lake Michigan 
species into the waterway. Although cyclopoids were collected 
at all locations, the occurrence of some species was lim.ited 
to specific navigation pools. 

With the exception of four sampling locations near 
Lake Michigan, densities of total zooplankton generally 
increased in a downstream direction. Intolerance to various 
water quality conditions may have limited rotifer abundance 
in the uppermost region of the waterway. 

Although the abundance of cladocerans at all locations 
was low in July, it increased notably in August and Septem- 
ber when Dresden Island, Marseilles, and Starved Rock lock 
and dam structures were closed for repairs. I suggest that 
increases in cladoceran numbers may have been a direct 
result of short term changes in the physical conditions of 
impoundment (decreases in water velocity, turbulence, turbid- 
ity, etc.) during that period. 

At the turn of the century, copepods constituted an 
insignificant fraction of the total population, but those 
organisn.s comprised between 10 and 50i of the total zooplankton 
in 1S7S. 

A cluster analysis using modified Jaccard indices re- 
vealed three to four general regions of the Illinois River based 
on similarity patterns of zooplankton communities. Generally, 
in terms of its zooplankton, the Illinois Waterway appeared 
to be more homogeneous in the upper and middle regions . 



Zooplankton 17-35 

Diversity index values for Illinois V/ater\cav zooplankton 
ranged from 1.4 to 3.4 during the 1978 investigation. There 
was no evidence of significant differences (0.05 level) be- 
tween the mean of values computed for the first six stations 
(above river mile 280), 

and the remaining sampling locations farther 
downstream. These trends suggest that, despite the poor 
water quality reported for the upper waterway, zooplankton 
were subsisting with greater success than expected. 

With the exception of the North Branch, the mean zoo- 
plankton ash-free biomasses of upper river stations (above 
river mile 272) were virtually the same. Downstream of Dres- 
den Island Lock and Dam, the mean biomass increased two- to 
five-fold from Marseilles to Peoria, respectively, and then 
dropped sharply at La Grange and Kampsville-Michaels Landing. 

PREDICTED EFFECTS OF INCREASED 
DIVERSION ON ILLINOIS VMTERIVAY ZOOPLANKTON 

While the overall quality of a river or stream is 
largely determined by the interaction of climate, basin- 
terrain characteristics, and land-use activities (Rickert 
and Hines, 1978:1114), the success of viable zooplankton 
communities in the Illinois Waterway is dependent primarily 
upon the hydrography of the stream and certain physicochemi - 
cal parameters. Since an analysis of one factor can rarely 
explain the changes incurred by the biota of flowing waters, 
the investigator must review several parameters together to 
determine the cause-effect relationships. The following 
summary briefly describes the primary conditions that in- 
fluence the biology of riverine zooplankton in the Illinois 
River. 

Velocity 

In 1899, Schroeder proposed that the amount of plank- 
ton in rivers was inversely proportional to the stream's 
gradient (in Greenburg 1964). Continuing one step further, 
Forbes and Richardson (1919), Galtsoff (1924), and Reinhard 
(1931) concluded that water velocity (which is generally a 
consequence of stream gradient) was the principal factor 
affecting river plankton. When drifting in faster currents, 
plankters have less time to multiply and thus produce 
fewer numbers per unit time and distance. Kofoid (1903) 
concluded that the age of water, water level fluctuations 
and the presence of dams in the Illinois River were the key 
to plankton survival : 

"Young streams have but few plankton. Impounded 
for 10-30 days, this barren water developed an 
abundant plankton crop. The rate of runoff and 
replacement of impounded waters influences plank- 
ton production, being greatest where runoff and 
renewal are least." 



Zooplankton 17-36 

He also believed that a stable hydrography was conducive to 
plankton growth and reproduction while flooding and/or high- 
ly fluctuating water levels were fatal. 

Reinhard (1931:419) resolved that age of water, water 
level stability, and current velocity were all phases of 
the same ph)'sical influence; thus, the emphasis should be 
placed on current since it is the distinguishing character- 
istic of river ecosystems. Continuing the theories of early 
investigators, Reinhard proposed, "with other conditions 
equal, the product i \"i ty of a stream is proportionate to the 
age of its water and inversely proportionate to its velo- 
city. " 

Changes of water velocity in the Illinois River due to 
flooding and increased water levels probablv would be detri- 
mental to zooDlankton development in the upper waterway. 



Turbidity 

Relatively few zooplankters can withstand the condi- 
tions that perpetrate high turbidity, i.e., shifting sub- 
strates and sedimentation, low light penetration, and high 
water temperatures (Berner, 1951:3). Turbidity in river 
waters is caused by the presence of suspended materials such 
as clays, silts, minute organic and inorganic particulate 
matter, and plankton. By impending the penetration of light, 
turbidity limits phyto- and periphyton development, and 
ultimately photosynthesis, and the utilization of dissolved 
oxygen by other trophic levels. In the lower Missouri 
River (Berner, 1951:5), high turbidity contributed to the 
paucity of all forms of plankton, and either directly or 
indirectly, controlled every limnological facet of the river 
ecosystem. In 1966, Williams observed that most streams 
carrying high silt loads were deficient in sizeable rotifer 
populations. High densities of rotifers were generally 
associated with waters of high clarity, the same waters 
that supported large numbers of phytoplankton. Although 
Williams (1966) hinted of a direct or indirect relationship 
between rotifers and phytoplankton in terms of a food re- 
lationship, others, including Kofoid (1903), Sabaneeff 
(1952), and Rylov (1940) in Winner (1975), and Colbert 
(1975) suggested that suspended solids either (1) inter- 
fered with the filter- feeding apparatus of rotifers and 
microcrustaceans , or (2) accumulated in the animals' guts 
and caused them to settle to the bottom. In some instances, 
however, large quantities of organic particulates were proven 
an excellent food resource for certain detritus-eating 
rotifers, cladocerans, and copepods. 



Zooplankton 



17-37 



Soil erosion, and the scouring and mixing of sediments 
by barge traffic, are the principal factors contributing to 
high levels or turbidity in the Illinois River. Turbidity 
plays an important role in reducing zooplankton abun- 
dance and diversity in regions having a high frequency of 
barge traffic. In regions relatively free of turbidity 
and various pollutional materials, however, the presence 
of some biogenic turbidity may be beneficial to detrital 
zooplankton feeders. 

Temperature 

The effects of temperature are most important in river- 
ine systems, especially in impounded waters adjacent to the 
river course and upstream of dams. Some groups of aquatic 
organisms (inducing zooplankton) require a narrow range of 
water temperature for maximum growth while others are toler- 
ant of wide variations (Ridley and Steel, 1975:572). Kofoid 
(1903) found that plankton populations were greatly reduced 
when water temperatures exceeded 26 C (80 F) . Greenburg 
(1964) suggested that water temperature was the single most 
important factor influencing plankton development in regions 
of the Sacramento River unaffected by tidal action. Uater 
temperature, stream flow, and BOD together accounted for 
nearly 60^ of the variation in plankton numbers. The reduct- 
ion in the number of rotifers in the Kalamazoo River was 
attributed to high temperatures as well as sedimentation and 
depletion of dissolved oxygen (Prins and Davis, 1966:9). I 
expect little change in zooplankton activity as a result of 
an alteration of temperature regimes due to the proposed 
diversion. 

Toxic Materials 



ly h 

and 

dive 

a li 

(And 

were 

a re 

viti 

the 



Final 
eavy m 
stream 
rsity , 
f e his 
erson , 

more 
suit o 
es . A 
body b 



ly, s 
etals 
s. Z 

inhi 
tory 

1950 
susce 
f bio 
Iso , 
eing 



ewage and industrial pollutants, particular- 
, are known to affect the plankton of rivers 
ooplankton may suffer a reduced species 
bited growth rates, or inability to complete 
stage. A general consensus of the literature 
) showed that Daphnia magna and other Crustacea 
ptible to heavy metals that fish, probably as 
accumulation through their filter- feeding acti- 
Crustacea are most sensitive at moulting, with 
the most permeable at that time (Anderson, 1950) 



Sources of pollution in the Illinois Waterway include 
municipal sewage wastes from Chicago and Peoria; industrial 
effluents (heavy metals, organic and inorganic compounds) 
discharged from food, textile, paper, and chemical indus- 
tries; agriculture (organic wastes, soil erosion, and bio- 
cides); and utilities, who discharge hot cooling waters from 
their power plants. All of these kinds of pollution, in- 
cluding others, are considered deleterious for zooplankton 
development in this river. 



Zooplankton 



17-38 



Dilution of these perturbations would be wholly beneficial to 
zooplankton, particularly in the Waterway above the con- 
fluence of the Des Plaines and Kankakee Rivers, 

Elimination of Backwaters 

Either draining or permanently flooding the Illinois 
River's natural bottomlands, backwater lakes, and sloughs 
could significantly lessen the total productivity of their 
zooplankton biota (Kofoid, 1903; Forbes and Richardson, 
1915, 1919; Purdy, 1930; Mills et al , 1966). As a case 
in point, the paucity of adjoining backwaters was considered 
to be largel}' responsible for the low densities of plankton 
in the lov.er Missouri River (Berner, 1951:5). 

As far as can be determined, diversion of Lake Michigan 
waters into the Illinois waterway would apparently have its 
greatest impact on zooplankton at Chicago and below river 
mile 231 on the lower river. In Chicago, increased diversion 
would dilute many toxicants and, consequently, could con- 
tribute toward a more favorable environment for zooplankton 
populations in that region. However, increased water 
velocities may extend pollutional materials further down- 
stream, thus retarding processes of natural purification 
and exposing organisms to municipal and industrial wastes 
for a longer duration. Populations in the lower river 
would be subject to increased water velocities as higher 
water levels would allow navigation locks at Peoria and 
La Grange to remain submerged; thus, normally impounded 
waters upstream of those structures would revert to more 
river-like conditions and thus reduce the abundance of 
open-water microcrustaceans . The navigation pools bet 
Lockport and Starved Rock will probably be little chan 
in terms of zooplankton populations as these regions 
promote the production of open-water and other typical 
lake species. It is probable that increased water lev 
would further change the character (increased turb 
and siltation of backwater lakes such that their pot 
for replenishing zooplankton in the main channel would 
greatly reduced. 



ween 
ged 



els 
idity 
ential 
be 



In conclusion, I predict that the effects of Lake 
Michigan diversion on zooplankton in the Illinois River 
would be neither wholly beneficial nor totally detrimental. 
Hynes (1960:68) summed it best by stating that most of the 
effects of man's activities are similar to those of natural 
phenomena; if the effects are not lethal, then the biota merely 
change and adapt, and thus change one type of river environ- 
ment into another. 



MITIGATIVE ACTIONS 
There would be little need for any mitigative action 



18-1 



CHAPTER 18: MACRO INVERTEBRATES 
R.E. Sparks 
HISTORICAL CRA\nES 



Historical changes in the benthos of the Illinois River 
have been well documented and discussed in detail elsewhere 
(Forbes and Richardson, 1913; Forbes and Richardson, 1 9 1 •=! : 
Richardson, 1921a; Richardson, 1921b; Richardson, 1925a: 
Richardson, 1925b; Richardson, 1928: Mjiis et al., 1966: 
11-13; Anderson, 1977: 47-54: Bellrose et al . , 1977: €66- 
C74; Sparks et al., 1979: 20-27). 

Following are the major im.pacts on macroinvertebrates 
in the Illinois River which have occurred in the past: 

(1) Organic pollution coming primarily from: the Chicago 
area, with some contribution from the Peoria-Pekin area, had 
practically eliminated or drastically altered macroinverte- 
brate communities in the entire Illinois River and its back- 
waters and bottomland lakes above La Grange (river m.ile 
80.0) by 192P. 

(2) Installation of sewage and industrial waste treat- 
ment facilities brought about a recovery of the macrobenthos 
in 1920-1925. 

(3) Installation of locks and dams, and the su>^sequent 
increase in boat traffic and dredging, starting in the 1930's, 
probably affected some species of macroinvertebrates, although 
it is difficult to determine precise cause-effect relation- 
ships (Bellrose et al., 1977: C66-C74; Sparks et al . , 1979: 
20-27) . 

(4) Some unknown factor practically eliminated fingernail 
clamiS (?'usculium trans versum and several other species of 
Musculium and Sphaerium ) and several snecies of snails from 
the reach of the river between the mouth of the Sangamon 
River and upper Peoria Lake (river mile 89.0 to mile 182.0) 
starting in 1955 and continuing down to the present time. 

(5) Increasing turbidity was probably responsible for 
the die-off of submerged aquatic vegetation which began in 
the late 1950 ;s, and which eliminated the "weed fauna", the 
macroinvertebrates such a? damselflv larvae (suborder zygoptera) 



Macroinvertebrates 18-2 



and dragonfly larvae (suborder anisoptera) which inhabit 
the submerged vegetation. 

The loss of the small inollusks, starting in 1PS5, affec- 
ted the bottom- feeding fish and the diving ducV.s which 
utilized the river during their spring and fall migrations. 
The loss of the weed fauna affected fish such as bluegills, 
which are primarily insectivorous most of their lives, 
as well as voung bass and crappie, which consume insects 
before shifting primarily to fish. The species which 
comprise the weed fauna furnish excellent food for fish 
(Pichardson, 1921a: 432). The importance of the weed 
fauna to higher- level consumers is shown by the fact that 
the biomass of weed fauna averaged 2,118 pounds/acre 
(2,374 kg/ha) in five classes of lakes and backwaters 
near Havana (mile 120.0) in 1914-1915 (Richardson. 1921a: 431 
432). The average biomass of weed fauna was eight times 
greater than the average biomass of bottom, fauna, such as 
fingernail clam.s and aquatic earthworms (class oligochaeta) , 
in the same lakes on a per-acre comparison. The average 
biomass of weed and bottom fauna in the lakes and backwaters, 
in turn, was twice as great as the biomass in the river 
proper . 



PRESENT CONDITIONS 

Benthic Macroinvertebrates 

Recent Surveys 

In the fall of 1975, Anderson (1977) took three to 
five replicate bottom samples with an Ekman dredge at each 
of 20 stations in the Illinois River from mile 18.9 to 
277.0 (see Figure 18-1). The major purpose of Anderson's 
study was to determine the distribution of fingernail clams, 
and other taxonomic groups were not identified bevond the 
family level of classification. A consulting firm, WAPORA 
(1974) conducted two-year biological studies at power plant 
sites near Hennepin (river mile 212.0), Havana (river mile 
118.6), and Meredosia (river mile 70.8). They collected 
bottom samples with a Ponar dredge and also set out artifi- 
cial substrates, and they identified organisms to species 
where possible. Colbert et al . (1975) took nine benthic 
samples in September 1975 between river mile 2.5 and 81.0 
and had the organisms identified to species where possible, 
by Midwest Aquatic Enterprises, Mahomet, Illinois (Colbert 
et al., 1975: 23). Biologists from the Metropolitan Sanitary 
District of Greater Chicago took three replicate bottom samnl 



es 



Macro invertebrates 



18-3 




O . CITIES 

^. LOO AND DAr< SITES 
■ • SAMPLING STATION 



Figure 18-1. Location of stations in the Illinois Piver where 
Anderson (1977) took bottom samples in the fall 
of 1975. 



Macroinvertebrates 18-4 



vith a Ponar dredge at each of IP sampling stations in the 
Chicago area waterv,'ays in 1975. Sampling runs were made in 
the summer, fall, and winter. Stations are plotted on a 
map in Figure 18-2. Stations 35, 74, and 49 were located 
in waterways at the three points where Lal:e ^'ichigan water 
enters the waterwav svstem: the North Shore Channel below 
the Wilmette Lock (station 35), the Chicago River just 
below the Chicago Harbor Lock (station 74), and in the 
Calumet River below Calumet Harbor (station 4Q) . Station 
84 was located the farthest downstream at mile 292.2 on 
the Sanitary and Ship Canal portion of the Illinois Water- 
way, and the remainder of the stations were located in 
waterways between station 84 and stations 35, 74, and 49. 

Present Distribution and Species Diversity 



In general. Tables 18-1 through 18-6 show that the 
benthos of the Illinois River is dominated by aquatic earth- 
worms and bloodworms (which are actually insect larvae, midges 
of the family chironomidae) . The greatest diversity of 
bottom- dwelling macroinvertebrates generally occurs in the 
lower 148 miles. Diversity generally decreases upstream, 
with the loss of small mollusks (snails and clams) and 
mayflies (family ephemeroptera) . Tables 18-3 to 18-6 and 
MSDGC (1978: 39ard42) show one exception to the trend of 
fewer species upstream: MSDHC stations 35 and 74, located 
in areas receiving some clean Lake Michigan water from lake 
inlets, had more snecies than downstream areas. In fact, 
station 74 was the only one of six stations in the northern 
portion of the Chicago River where sideswimmers (or scuds, 
order anphipoda) and clams were present. A variety of 
species, including crayfish (Family astacidae, ^^SDGC , 1978: 
50), also was found in the Calumet River (stations 4Q, 55, 
56) below the Lake ^'ichigan inlet, but only one species of 
aquatic earthworm became dominant further downstream where 
effluent entered from the Calumet Sewage Treatment Plant 
(Tables 18-3 to 18-5 and MSrr;C, 1978: 50-52). Some of the 
species, such as sideswimmers, found near the Lake inlets, 
are in fact residents of the Lake which have been carried 
into the waterway (>-'SDnc, 1978: 1-2). 

Factors Affecting Present Distribution 

The decline of diversity of macroinvertebrates in the 
upstream direction, toward Chicago, indicates that municipal 
and industrial wastes from the Chicago area are probably 
affecting the benthos. 



Macro invertebrates 



18-5 



• RESEARCH STATION 

O FISH STATION 

■ TREATMENT PLANT 



Lincoln 



35 



NSTP OUTFALL 



^ 



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Michigan 



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onnti 



CTP OUTFALL- 
^« 76 



c?^130th 
'55 



Hoisted Indiana ^o/ 

Asfilond T 



84 < 



16th St. 



Figure 18-2. Location of stations (identified as research 

stations, •) in the Chicago area waterways where 
biologists from the Metropolitan Sanitary District 
of Greater Chicago took bottom samples in the 
summer, fall, and winter of 1975. 



Macro invertebrates 



18-6 



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Macroinvertebra It ;= 1? 



Although Anderson (1977) did not tal'e anv fingernail 
clams above mile 107 in 1P75 (see Table 18-1), other studies 
have shovn that fingernail clams occur in tributaries and 
in isolated poc1(Cts in the Illinois River. MSDHC (1978: 
47, Sn) collected fingernail clams in the Calum.et River and 
in the Chicago River and its south branch. All locations 
vere fairly close to inlets from Lake ffichigan. fingernail 
clams occur in the Des Plaines River above the entrance of 
the Chicago Sanitary and Ship Canal (personal coinir.unication , 
August, 1977. Mr. Thomas A. Butts, Illinois State Water 
Survey, Peoria, Illinois), and fingernail clamis are regu- 
larly impinged on the intake screens at the R.S. V.'allace 
Power Station located at river m.ile 162.5 on Lower Peoria 
Lake (personal communication, 1 June 1977, Mr. Huv R. 
>!cConnell, V.'APOPA , Inc., Charleston, Illinois). The finger- 
nail clams taken at the power plant mav have washed down- 
stream from populations which managed to survive in areas 
of Peoria Lake where snring water enters through the river 
bottom. There are several areas in Peoria Lake, such as the 
vicinity of Spring Bay (mile 173-180), where spring water is 
known to enter the lake. 

Between June and November, 1973, WAPORA took 1 finger- 
nail clam in 21 Ponar dredge samples near Hennepin (mile 
212.0) and 9 fingernail clams in 21 Ponar dredge samples 
near Havana (mile 118.6). In the reach of the Illinois 
River from mile 89.0 to mile 145.3, which includes the 
Havana region, a bedrock valley overlain with sand deposits 
lies to the east of the Illinois River. Groundwater flows 
through the sand into the Illinois River at the rate of 
about 8.75 m'/s (309 cfs) during lov-flow conditions (Singh 
and Stall, 1973: 19). The good quality groundwater flow^ing 
into the river along the sandy eastern bluffs may m.ake some 
areas marginally suitable for fingernail clam.s. However, 
the clams apparently are still not abundant enough to attract 
flocks of diving ducks (see chapter on waterfowl) . 

Union id Mussels 

Recent Distribution 

The results of a 1966 survey of the Unionid mussels in 
the Illinois River by K.C. Starrett showed that both the 
number of mussels (Figure 18-3) and the number of species 
(Figure 18-4) declined in the upstream direction, toward 
Chicago. No living mussels were taken in the uppermost reach of 
the river in the 1960's, and the original mussel population 
there had been eliminated as early as 1912. 

In 1966 , the commercial mussel fishery was confined to the lower 
87 miles of the river, but in 1969 it resumed in the vicinity of Peoria, 
where a substantial population occurred at mile 162.0 (Figure 18-5). 

I 



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SIBSSnw JC SQNIM JO a38rtnN 



Macroinvertebrates 18-17 

Factors Affectine Present Distribution 

Figure 18-3 shows that there is a poor correlation between 
dissolved oxygen levels and number of mussels. In La Hrange 
Pool at mile 100, for example, mussels were living in water 
containing less dissolved oxygen than was observed in the 
upper river, where no living mussels were found. Pollutants 
which occur in municipal sewage effluent, such as ammonia, 
occur at higher levels in the upper Illinois Piver than in 
the lower reaches (Figure IS-S). Un-ionized ammonia is toxic 
to fish and the percent of the total ammonia which exists 
in the un-ionized form is governed by pH and temperature. 

The proposed increase in diversion could conceivably 
dilute ammonia concentrations in the upper Illinois River. 
Unfortunately, there is almost no information on the 
toxicity of ammonia to invertebrates in general, or 
unionid mussels ir particular. Anderson et al. (1978: 74- 
75) reported that .60 mg/1 un-ionized ammonia nitrogen (all 
concentrations are expressed as amjponia nitrogen, NH,-N) 
killed fingernail clams, .34 mg/1 reduced their growth, 
and .03 m.g/1 markedly reduced the beating rate of cilia 
on the gills of the clams. A concentration of 0.?4 mg/1 
NHj-N is lethal to ^0% of the Paphnia magna exposed to 
that concentration for 2 days (European Inland T^isheries 
Advisory Commission, 1970). Anderson et al. (1978: 75) found 
that the gills of the freshwater Unionid mussel Elliptio 
complanata were less sensitive to un-ionized amimonia than 
the gills of the fingernail clam. >'ean un-ionized ammonia 
concentrations in the Illinois Piver between mile 119.5 and 
165.8 in 1975 were below .03 mg/1 NH3-N, but the maximum 
values of .048 to .125 exceeded the levels known to affect 
the gills of fingernail clams. Starrett (1971: 345) did 
not feel that the inverse relationship between mussel life 
and ammonia concentrations in the river necessarily implied 
a causal relationship: 

This relationship between mussel life and am- 
monia nitrogen (N) in the river may be considered 
either suggestive or accidental. The chemistry of 
a polluted river, such as the Illinois, is, in the 
author's opinion, too complex to allow one to infer 
from field data that one chemical or condition 
was the sole lim.iting factor. 

Prift Organisms 
Def ini tion 

When artificial substrates consisting of wood, masonite, 
or other solid material are suspended in the water column. 



Macro invertebrates 



18-18 




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Macroinvertebrates 18-19 



they can be colonized by organisms Vnown as the "drift", 
usually aquatic insects which periodically sviir up or 
allow themselves to be carried in the water current so thev 
can drift doAvnstream and colonize new areas. These or- 
ganisms characteristically are found on solid substrates, 
such as gravel, shell beds, or logs, rather than on mud. 

Recent Surveys of Drift Organisms 

In 1967 and 1978 the Illinois Environmental Protection 
Agency (lEPA) conducted surveys of macroinvertebrates in 
the Illinois Piver and some of its tributary streams. The 
tributary streams were sampled by wading and hand-picVing 
organism.s from the bottom, material, while the Illinois 
River was sampled with modified Hester-Dendy artificial sub- 
strates. The purpose of the 1978 survey of the Illinois 
River was to determine whether water quality in the river, 
as indicated by the presence and abundance of certain 
species of macroinvertebrates, had im:proved in the 11 years 
since the 1967 survey. The purpose of the survevs of the 
tributary streams was to determine whether drift organisms 
were available in the tributaries for colonization of ar- 
tificial substrates in the main river (personal communi- 
cation, 27 June 1979, Mr. William J. Tucker, Supervisor cf 
the Water Quality Monitoring Subunit, Division of V.'ater 
Pollution Control, Illinois Environmental Protection Agency). 

In 1973, the environm.ental consulting firm, WAPi^RA, 
collected drift organisms from both the Illinois River and 
its tributaries. In 1976, another environmental firm., 
Dames and >'oore, collected invertebrates from the tribu- 
taries only. Both firms supplied copies of their data 
to the Illinois Environmental Protection Agency. The 1973 and 
the 19 76 Dames and Moore data are inTable 18-6. In 1976 and 1977, 
the Illinois State Water Survey maintained modified Hester-Dendy 
artificial substrates at seven of the locks and dam.s along the 
Illinois River and at Kampsville (river mile 3 2.0) in the Alton 
Pool (Hill and Evans, 1978: 1-3). The Illinois State Water Survey 
reported the number of individuals, number of taxonomic groups, 
and also used an aquatic environment classification system 
developed by Tucker and Ettinger of the Illinois Environmental 
Protection Agency (lEPA, 1974). 

lEPA Classification of Aquatic Environments 

The lEPA used the macroi nvertebrate data collected by 
themselves and the consulting firms to classify the aquatic 
environments in the tributaries and the main stem of the 
Illinois River. Some explanation of the lEPA classification 
procedure is necessary. The first step in the procedure is 



Macroinvertebrates 18-20 



to classify the species of riacroinvertebrates accordinp 
to their tolerance of high organic loading, low dissolved 
oxygen levels, and pH extreines . The tolerance classifica- 
tion is given below (lEPA, 1Q74); 

TOLERANT: Those organisms that tolerate and prefer 
environments that contain a high amount of organic material. 
Polluted environm.ent . 

INTnLERJ\?vT : Those organisms that must have ideal 
conditions in respect to dissolved oxygen, biochem.ical 
oxygen demand and hydrogen ion concentration. Balanced 
environment . 

MODERATE: Those organisms that prefer an environment 
between tolerant and intolerant. Unbalanced to semi- 
polluted environment, 

T'ACULTATIVE : Those organismis that can survive in any 
of the environments described except in environments of 
severe pollution. 

The next step is to classify the aquatic environment, 
based on the percent of tolerant and intolerant species of 
macroinvertebrates in the sample: 

1. A BALANCED EN\^IRON>rENT is one in which conditions 
are maintained capable of supporting a variety of organisms, 
mostly intolerant species, from various taxonomic groups. 

Intolerant present > 50% 

^'oderate, Facultative and Tolerant usually present <50l 

2. AN UNBALANCED ENVIRON^^ENT is one in which the 
balance of life, as described for a balanced environment, has 
been disrupted but not destroyed. The population num.bers of 
some of the intolerant forms are reduced and an increase 
beocmes apparent in some of the more tolerant forms. 

Intolerant present <Sn% but >10^ 

Moderate, Facultative, and Tolerant usually present >50? 

3. A SEWJ-POLLUTED ENVIROWIENT is one in which the 
balance of life found in a balanced environment is destroved. 
Intolerant forms are completely absent or reduced to a mini- 
mum and the environment is composed predoiminantly of tolerant 
forms . 

Intolerant present <^0% 

Moderate, Facultative, and Tolerant usually present >POl 



Macroinvertebrates 18-21 



4. A POLLUTED EMaPON^TNT is one in which onlv the very 
tolerant forms are able to exist. These are usually present 
in great numbers unless excluded from the environirent by 
severe conditions. 

Tolerant present lOO'o 

Organisms which are not adapted to inhabit a polluted 
environment are occasionally collected as a result of fac- 
tors produced bv the drift and are not representative . 

5. Natural or artificial bare area. 

Modification of lEPA Classification 

The Illinois State Water Survey (Hill and Evans, 1978: 
6) modified the methods used bv the lEPA. Although lEPA 
classifies some species of midges (familv chironomidae) as 
tolerant, and others as moderate, facultative, or intolerant, 
the ISV.'S identified the chironomidae to the family level 
and classed the family as a whole as tolerant. The lEPA 
classifies the damselflv genus Ischnura as intolerant, 
while the ISWS found Ischnura associated with tolerant 
organisms at a station with low dissolved oxygen levels, 
and hence regarded Ischnura as moderately tolerant . The I SKS 
also used a point svstem for the environmental classifica- 
tion, instead of the descriptive words used bv the lEPA, 
to permit calculation of numerical averages. 

Distribution of Pollution-Tolerant and Intolerant Drift Organisms 

Table '18-7 shows that most of the tributary streams 
along the Illinois River contain macroinvertebrate commu- 
nities classified by the Illinois Environmental Protection 
Agency as balanced, meaning that intolerant organisms 
comprise S0% or more of the total number of species. The 
fact that the lEPA found pollution- intolerant drift organisms 
in the tributary streams means that thev were available to 
colonize the Illinois River wherever suitable substrates and 
suitable water quality existed. The lEPA results shown in 
Table 18-8 and Figure 18-6 show that the upper Illinois 
River was generally classed as semi -polluted to unbalanced 
in both 1967 and 1978, but that the middle portion of the 
river between miles 120 and 170 improved from unbalanced 
or semi-polluted to balanced between 1967 and 1978. There 
was an anomalous decline from balanced to semi-polluted at 
river mile 88.5. 

Figure 18-7 shows that the results obtained by the 
Illinois State Water Survev follow the same trend as those 



Macro invertebrates 



18-22 



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Macro invertebrates 



18-23 



Table 18-8. Comparison of biological conditions in the Illinois 
River as dcteririned bv invertebrates on plate 
samplers in 1967, 1978, and 1973. (Data supplied 
by William J. Tucker, Aquatic Biologist, Illinois 
Environmental Protection Agency.) 















KAPORA 




River 


Sept. Oct 


Aug. 


Oct 


Oct. 


Citv 


Mile 


1967 196' 


1978 


197f 


> 1973 


Joliet^g 


285.7 


S.P 


S.P 


S.P. 


S.P 


. 


Lorenzo 


273.6 


U.B 


S.P 


S.P. 


S.P 


- 


Morris 


263.4 


S.P 


Pol 


S.P. 


S.P 


Pol. 


Seneca 


252.7 


U.B 


S.P 


S.P. 


S.P 


S.P. 


Marseilles 


247.4 


U.B 


U.B 


U.B. 


S.P 


U.B. 


Ottawa 


239.7 


U.B 


U.B 


U.B. 


U.B 


S.P. 


La Salle 


224.8 


U.B 


Bal 


.c 


U.B 


Bal. 


Peru 


222.0 


S.P 


U.B 


, U.B. 

D .C 


U.B 


S.P. 


Spring Valley 


218.4 


S.P 


U.B 


S.P 


- 


Hennepin 


207.6 


S.P 


U.B 


U.B. 


S.P 


Pol. 


Henry 


196.0 


S.P 


U.B 


U.B. 


S.P 


S.P. 


Lacon 


189.1 


U.B 


S.P 


U.B.b 


S.P 


U.B. 


Chillicothe 


180.4 


U.B 


S.P 


U.B.D 


Bal 


U.B. 


Peoria - PWS 


166.2 


U.B 


U.B 


U.B. 


Bal 


Bal. 


Peoria - ISWS 


161 .6 


S.P 


S.P 


U.B.b 


Bal 


- 


Pekin 


153.0 


S.P 


U.B 


Bal. 


Bal 


b ";»■ 


Kingston Mines 


145.4 


S.P 


S.P 


.c 


Bal 


Banner 


136.8 


S.P 


U.B 


-C 


.c 


Pol. 


Liverpool 


128.1 


S.P 


S.P 


U.B.^ 


Bal 


Bal . 


Havana 


119.6 


U.B 


Bal 


Bal.^ 


Bal 


Bal. 


Browning 


97.2 


U.B 


U.B 


U.B.b 


U.B 


U.B. 


Frederick 


91 .7 


U.B 


S.P 


U.B. 
b U.B."^ 


U.B 


Bal. 


Beardstown 


88.5 


Bal 


Bal 


S.P 


U.B. 


La Grange 


80.3 


U.B 


b U.B 


Bal 


- 


Meredosia 


71 .2 


.c 


.c 


.c 
U.B.^ 


U.B 


- 


Valley City 


61 .3 


- 


- 


U.B 


- 


Florence 


55. 3 


Bal 


U.B 


.c 


U.B 


- 


Pearl 


42.7 


Bal 


Bal 


.c 

'^ Bal.^ 


U.B 


- 


Kampsville 


32.1 


.c 


U.B 


Bal 


- 


Hardin 


21 .6 


Bal 


Bal 


U.B. 


Bal 


- 


Pere Marquette 


7.2 


- 


- 


U.B. 
U.B.t' 


U.B 


- 


Brussels 


3.6 


Bal 


U.B 


U.B 


- 


Grafton 


0.7 


Bal 


U.B 


U.B. 


Bal 


' 



Des Plaines River. 

Invertebrates hand-picked from bottom material, rather than 
taken from samplers. 

Sam.pl er lost. 



^^acro invertebrates 



18-24 




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Macro invertebrates 



18-25 



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Vacroinvertebrates 18-26 



obtained by the lEPA: the upper Illinois River is generally 
classed as wore polluted than the dov.-ns tream reaches. In 
addition, the number of individuals and the number of 
species of drift organisms colonizing the artificial sub- 
strates increases in the downstream direction, away from 
Chicago (figure 18-7). In T^igure 18-7, note that the 
investigators from the Illinois State Water Survey (Hill 
and Evans, 1^578: 6-7) felt that clean water from the Kan- 
kakee River and drift organisms from the Kankakee were 
responsible for both the unusually high num^^ers of indi- 
viduals and taxa and the improvement in the environmental 
classification at river mile 271.5, just 1.5 miles down- 
stream from the mouth of the Kankakee. Hill and Evans 
(1978: 10-11) concluded that there was an apparent 
downstream improvement in communities of drift organisms 
colonizing artificial substrates in the Illinois River 
and that this improvement was associated v.-ith higher 
dissolved oxygen concentrations (Figure 1--7). They 
recommended additional studies, including gathering of 
physical-chemical data at the same time biological data 
are gathered, to further define the water quality charac- 
teristics associated with a healthy comjrunity of drift 
organisms . 



Contrast Between Benthic and Drift Communities 

The improvement in drift communities colonizing arti- 
ficial substrate samplers in Peoria Lake (see Figure 18-6) 
is not paralleled by a corresponding increase in the num- 
bers and kinds of small m.acroinvertebrates on the bottom 
(see Table 18-1) . 

Possible explanations for the difference in macro- 
invertebrate communities on the bottom and on the samplers 
are: 

(1) The organisms that live on the mud bottom differ 

in their tolerance to pollution from organisms that colonize 
artificial substrates. 

(2) Dissolved oxvgen is lower on the bottom than in 
the water column. 

(3) Some toxic factor occurs at higher concentrations 
near the bottom than in the water column. 

(4) The bottom sediments themselves are limiting the 
benthic organisms, rather than the water quality. 

The first explanation can be eliminated, because many 
of the benthic organisns which have declined in the Illinois 
River, such as fingernail clams, are tolerant of low oxvgen 



Macroinvertebrates 18-27 



levels and fairly high orpanic loads. In fact, fingernail 
clam populations in the middle section of the Illinois Piver 
increased for a time after the Chicago Sanitary and Ship 
Canal was opened and sewage was flushed into the river 
from Chicago (Forbes and Pichardson, 1<513). Although item 
2 may furnish an explanation for the loss of benthic or- 
ganismis in bottomland lakes and backwaters, where oxygen 
levels sometimes approach zero during the suirirer (Illinois 
Natural History Survev, unpublished data), it does not 
explain the loss of benthos in other areas where there is 
appreciable current and the water seems to be well mixed 
from top to bottom. For the same reason, it is unlikely 
that toxicants are stratified in the water column, and r.ore 
concentrated near the bottom. 

Although the effects of water quality on som.e aquatic 
organisms, such as fish, have been investigated, little 
is known about the effects of water quality and sedim.ent 
quality on bottom-dAvel ling organisms. Anderson et al. 
(1978: 85) showed that raw Illinois River water almost 
completely inhibited the beating of cilia on the isola- 
ted gills of fingernail clamiS within three hours, while 
normal ciliary rates were maintained in well water for at 
least 6 hours. The water sample which inhibited the cilia 
was taken from the Illinois River at Havana (river mile 120) 
on 5 October 1P77. More recently. Sparks and Pa^iaro (Illi- 
nois Natural History Survey, unpublished data) have shown 
that sediment taken from Quiver Lake, a bottomland lake 
near Havana where fingernail clams died out in 1955, re- 
duces the transport rate of particles across the gills of 
fingernail clams. The greatest reduction occurred with 
sediment 4 to 8 cm deep, while the 0-4 cm layer reduced 
the particle transport rate somewhat less, and the deeper 
layers below 8 cm had even less of an effect. These results 
indicate that there is some factor associated with the water 
and sediment in the Illinois Piver which impairs the normal 
ciliary activity of the gills in the fingernail clam. 
Since the cilia produce the water currents which enable the 
clam to draw oxvgenated water over the gills and to trap 
food particles, any impairment of this activity would prob- 
ably have a long-term effect on the clam, even if the clam. 
did not die immediately. 



Another problem with sediments in the Illinois River 
may be that they are too watery to furnish a good substrate 
for fingernail clams and other mud-dwelling organisms, ^'anv 
of these organisms live close to the mud-water interface, 
and draw their food from the overlying water. For example, 
mayflies of the genus Hexagenia construct U-shaped burrows 
in the mud and pump water through the burrows with undula- 
ting movements of their abdomens. Fingernail clams burrow 
in the mud, and extend their siphons into the overlying 



Macroinvertebia Lcs 18-^. 



water. In much of the Illinois River, there is no well- 
defined mud-water interface, onlv an imperceptible gradation 
from muddv water to vaterv sediment. Also, the bottom is 
continually resuspended by boat traffic in the main channel 
and by wind-generated waves in the larger laVes and back- 
waters . 

The watery sediment might be either the cause or the 
result of the decline in benthos. It mav be that som.e 
toxic factor reduced or killed out the benthic macroinver- 
tebrates starting in the 1950's, and the sediments became 
more watery and dispersed following the die-off. The 
other possibility is that the sediment became more water>- 
during the mid-1950's as a result of some other factors, 
thereby eliminating groups of organism.s which need a 
definec3 mud-water interface to survive. Unionid mussels 
and fingernail clams filter particles from the water and 
excrete undigested particles in strands of mucus. Snails 
lay down mucus trails over the bottom. Aquatic earthworms 
and bloodworms (midge larvae) ingest sediment and organic 
particles, assimilate some of the organic matter, and pass 
undigested matter as compact fecal pellets. Thus, the 
burrowing and feeding activities of benthic macroinverte- 
brates may help to remiove sedim.ent from overlying water 
and to form, aerate, and compact the hvdrosoil. formation 
and maintenance of the hydrosoil m.ay have been altered 
drastically when the benthic macroinvertebrates declined 
in the mid- 1950's. 

By utilizing organic matter that would ultimately decay, 
benthic macroinvertebrates may reduce the potential oxygen 
demand exerted by the sediment, even though they consume 
some oxygen themselves. The sediment in the Chicago Water- 
wavs , and in the Illinois River and its bottomland lakes 
today exerts a high oxygen demand that has the potential 
to remove oxygen from the overlying water (Lee et al., 
1976: 15-18; Polls and Spielman, 1977: 19-21). 

POSSIBLE EFFECTS OF INCREASED DIVERSION ON MACROIN^^ERTEBRATES 

Possible effects of increased diversion on macroinvertebrate 
in the Illinois River include the following: 

(1) Dilution of organic and toxic wastes results in 
better water quality during low-flow periods. 

(2) Expansion of aquatic habitat available during the 
low- flow periods. 



^tacroinvertebrates 18-29 



(3) Sedinents that are toxic or otherwise ursuitable 
for macroinvertehrates wash further downstream. 

(4) Sediment deposits do not change location, but sedi- 
ment Quality rather than water quality remains a limiting 
factor for benthic macroinvertehrates. 

Dilution of effluents from Chicago with an increased 
amount of La>:e Michigan water might improve oxygen levels 
and decrease the concentration of toxic substances, such 
as am.monia. Macroinvertehrates which drift into the Illi- 
nois River from tributary streams might increase the rate 
of colonization and survival on suitable firm substrates. 
Since the bed of the upper Illinois River contains more 
gravel and rock than the river below Starved Pock Dam, 
there are suitable substrates available for colonization 
in the upper river. However, the Illinois River below 
the Starved Rock Dam is characterized by soft mud bottoms, 
and drift organisms entering fromi tributaries or from the 
upper Illinois River would not find suitable firm substrates. 
It is also unlikely that suitable su^-strates, in the form. 
of rooted aquatic plants, would reappear in the mdddle and 
lower sections of the river because the plants are limited 
by turbidity and constant agitation of the bottom rather 
than by chemical characteristics of the water. Without 
the development of a weed fauna or improvement in sediment 
quality, the increase of drift organisms to the middle and 
lower sections of the Illinois River would have little 
significance in terms of the whole ecosystem.. Improvements 
of the food supply for bottom- feeding fish, juvenile game- 
fish, and diving ducks would require restoration of the 
snails, fingernail clams, mayflies, and other insects 
which inhabit soft mud bottoms, or restoration of members 
of the weed fauna. 

Diversion will increase the quantity of aquatic habitat 
available in backwaters and lakes, but macroinvertehrates 
are unlikely to benefit because they are limited by the 
quality of the habitat, which is not likely to change. Ad- 
dition of 1-2 ft of water to lakes and backwaters during 
the summer low-flow period is not likelv to prevent wind- 
generated waves from continually resuspending the bottorri, 
thereby keeping the lakes turbid. Submerged aquatic plants 
are not likely to develop, therefore the v/eed fauna will 
not reestablish itself Suspended and resuspended sedi- 
ment will continue to exert an oxygen demand on the overlying 
water. The macroinvertehrates that are presently found in 
the river and backwaters, such as midges and cligochaetes . 
can withstand fairlv low oxvgen levels, and it is unlikely 
that oxygen levels will improve to the point where species 



^'acroinvertebrates 18-30 



vhich have hiqher oxvpen requirements, such as ravflies, 
can substantial Iv increase their t)opulation. As mentioned 
above, the watery sedinent characteristic of the bacV.vaters 
is unsuitable for many ):inds of macroinvertebrates and . 
probablv vill not improve as a result of the diversion. 

Both the phvsical and chemical characteristics of the 
sediment ir the Illinois ^iver and in the waterwavs in the 
Chicago area remain a major limiting factor for the macro- 
invertebrates, ^tathis and Cummings (1<^7": 1574) reported 
that heavv metals occur at higher levels in the sediments 
of the Illinois River than in relatively unpolluted tri- 
butaries to the Illinois. The Chicago District of the 
Corps of Engineers (197P: Table 15, pages 113-118) compiled 
data which showed high levels of toxic metals, phenol, 
cvanide, and PCEs occur in sediments in som.e reaches of the 
Chicago area waterways. As mentioned above. Sparks and 
Paparo found that surface lavers of sediment in the Havana 
region are toxic to the gills of fingernail clams. Sparks 
and Walter (Illinois Natural Kistorv Survey, unpublished 
data) found that snails ( Phvsa ) maintained in cages at 
two locations in the Illinois River rapidlv accumulated 
dieldrin, and that the rate of accumulation had not leveled 
off bv the time the experiment was terminated after 8 davs . 

If the increased diversion scours sediments out of 
portions of the Chicago area waterways, the habitat for 
macroinvertebrates mav improve where toxic, watery, or 
oxygen-dem.anding sediments are removed, but becom.e de- 
graded further downstream, where the sediments deposit. 
If the increased diversion does not scour sediments, they 
will remain as a factor limiting the bottom.- dwelling organisms 

SU»?'ARY 



If the increased diversion improves water quality and 
oxygen levels in the upper Illinois River, an increase in 
the numbers and kinds of drift macroinvertebrates which 
colonize solid substrates would be expected. Since Lake 
Michigan could not act as an upstream source for drift 
organisms, which are characteristic of streams and rivers, 
the colonization of a cleaner Illinois River would probably 
proceed from clean downstream tributaries, such as the • 
Kankakee River. However, in the bulk of the Illinois River 
and bottomland lakes below the Starved Rock dam, no increase 
in suitable substrates, such as furnished by rooted aquatic 
plants, mussel beds, or firm mud bottoms, is expected to 
result from the increased diversion. 



CHAPTER 19: FISH 



K.S. Lubinski, R.E. Sparks, W.U. Brigham, D. McCormick, 

and E.A. Atwood 



INTRODUCTION 



Fish populations in the Illinois Waterway have attracted 
the attention of fishermen and biologists since the last 
half of the 19th century and have been the subject of numer- 
ous technical and popular articles. Recent articles that 
have detailed the historical changes in the Waterway's 
fisheries resources have been Sparks et al. (1979), Brigham 
et al. (1978), Dennison (1978), Bellrose et al. (1977), 
Sparks (1977), Starrett (1972), and Mills et al. (1966). 



Objectives 

Rather than restate the numerous observations and 
conclusions reached in the reports listed above, we have 
restricted our treatment of the river's fish populations 
such that the objectives of this chapter are: 1) to describe 
the current status of fish populations in the waterway, 
and 2) to assess the potential impacts of increased diver- 
sion on them. 



FISH POPULATIONS OF THE ILLINOIS WATERWAY 

Data Bases and Project Areas 

The current fish populations of the Illinois V.'aterway 
were assessed using a combination of published and unpub- 
lished reports and data, and sampling surveys made possible 
by this study. Major differences existed between the data 
bases used to describe fish populations in the Chicago-area 
reaches of the waterway and those used to assess fish popu- 
lations in the Illinois River. These differences, which are 
detailed in the following sections, required that these two 
areas be discussed separately in this chapter. The only 
exceptions to this are Tables 19-2 and 19-3 which are com- 
piled using data from both areas. 



Illinois Waterway Fish 19-2 



Chicago-Area Reaches 

This section of the study is limited to northeastern 
Illinois (Cook, DuPage, and Will Counties) (Figure 19-1). 
This area was divided into 10 watershed subunits following 
guidelines provided by the U.S. Army Corps of Engineers 
(Figure 19-1, Table 19-1). Additional areas were included 
to expand the perspective of possible impact areas of the 
diversion project. These additional areas include Lake 
Michigan, the Calumet River, and adjacent waterways (tribu- 
taries to the Illinois Waterway). 

Under contract to the Northeastern Illinois Planning 
Commission, biologists of the Metropolitan Sanitary District 
of Greater Chicago conducted an inventory of the fishes in 
a number of key rivers and streams in northeastern Illinois 
in 1976. The majority of the assessments made on the fish 
populations in the Chicago-area reaches of the waterway 
were based on these data. Some of these data were also 
discussed in Brigham et al. (1978). 

Additional data involving the presence or absence of 
various fish species in each of the watersheds were taken 
from Illinois Natural History Survey records. The Survey 
collections were secured from sites throughout the watershed 
during two time spans, 1876 through 1905, and post-1950. 

Fish collections were not taken from the Kankakee River, 
an adjacent waterway, during the Metropolitan Sanitary 
District of Greater Chicago 1976 inventory. Data for this 
area were obtained from the Illinois Natural History Survey 
records. Fishery data for the Kankakee River were supple- 
mented with collections by Westinghouse (1973, 1975). The 
Lake Michigan watershed was reviewed using the fishery data 
presented in Brigham (1976). 

Illinois River 

The Illinois River (Figure 1-1) is the principal component 
of the Illinois Waterway and the river proper begins in the 
Dresden Pool of the waterway at the confluence of the Kankakee 
and Des Plaines Rivers. The observations and conclusions in 
this chapter relating to fish populations in the Illinois River 
are based on Illinois Natural History Survey electrof ishing 
data, the results of minnow seine and hoopnetting surveys 
conducted in 1978 and 1979, and recent literature not avail- 
able at the time the articles mentioned above were written. 



Illinois Waterway Fish 



19-3 




Figure 19-1. Locations of 10 v.-atershed suhunits of the 

upper Illinois Katerwav, Cook, DuPage, and Will 
Counties, Illinois. 



Illinois Waterwav ^ish 



l"-4 



Table 1 9-1 J)cscript ion of the ten watersheds in the Upper 
Illinois Waterway. 



Subdivis ion 



Location 



North Shore Channel 



North Branch of the 
Chicago River 



Chicago River 



South Branch 
Chicago River 



Chicago Sanitary 
and Ship Canal 



6. Calumet River 



7. Little Calumet 
River 



8. Calumet Sag 
Channel 



Includes the North Shore Channel 
extending from Lake Michigan to 
its confluence with the North 
Branch of the Chicago River. 

Includes that portion of the 
North Branch from the North 
Shore Channel confluence to the 
Chicago River confluence. 

Includes the Chicago River 
from its origin at the Lake 
Michigan shore to the junction 
of the North and South Branches 
of the Chicago River. 

Includes the South Branch and 
its tributaries from its origin 
at the confluence of the Chicago 
River to Ashland Avenue. 

Includes the Chicago Sanitary 
and Ship Canal from its origin 
at Ashland Avenue to its con- 
fluence with the Des Plaines 
River northeast of Joliet. 

Includes the Calumet River and 
its tributaries from its origin 
at Lake Michigan shoreline to 
the T.J. O'Brien Lock. 

Includes the portion of the 
Little Calumet River from T.J. 
O'Brien Lock to the river's 
confluence with the Calumet 
Sag Channel . 

Includes the Calumet Sag Channel 
and its tributaries from its 
origin from the Little Calumet 
River to its confluence with the 
Chicago Sanitary and Ship Canal. 



Sheet 1 of 2 



Illinois Waterv/av Pish 



19-5 



Table 10-3 Concluded 



Subdivision 



Location 



9. Brandon Road Pool 



Includes the Des Plaines River 
and its tributaries from the 
Des Plaines River - Chicago 
Sanitary and Ship Canal con- 
fluence to the Brandon Lock. 



10. Dresden Island Pool 



Includes the Des Plaines River 
and its tributaries from the 
Brandon Lock to the confluence 
of the Des Plaines River with 
the Kankakee River to form the 
Illinois River. 



Sheet 2 of 2 



Illinois Waterway Fish 19-6 

The INHS electrof ishing data used in this chapter repre- 
sent the most continuous set of annual fisheries data avail- 
able on the Illinois River. The electrof ishing data used 
in this report covered the period 1959-1979. 

The minnow seine and hoopnetting programs described in 
this chapter were conducted to provide specific additional 
fisheries data for this study. The minnow seine program 
was oriented toward assessing both the distribution and 
abundance of existing small-fish populations in the river. 
The hoopnetting program was designed 1) to supplement the 
electrof ishing program by sampling sites and habitats not 
typically covered by the electrof ishing program and by obtain- 
ing additional information on species (such as catfish) that 
are difficult to obtain using shocking techniques and 
2) to compare current hoopnetting catch results to those 
obtained from the river before electrof ishing became our 
primary annual sampling technique. 

Sampling Stations 

Chicago-Area Reaches 

During the Northeastern Illinois Planning Commission 
fish inventory described earlier, collections were made at 
248 sites from April through December of 1976. Twenty- 
eight of the sites were located on the diversion waterway 
and three were located in Lake Michigan. These stations are 
described in Appendix G, Table G-1, 

Illinois River 

Electrof ishing stations . Electrof ishing on the Illinois 
River was initiated in 1957 by Dr. William C. Starrett of 
the Illinois Natural History Survey, but stations were not 
established on the entire length of the river or every year 
until 1959. By 1979, twenty-four stations had been estab- 
lished. Stations were added in subsequent years to fill in 
reaches of the river where previous stations were far apart, 
where there were unique habitats, or where there was pre- 
viously only one station in a navigation pool. The locations 
and years in which stations were added were: 

Location Year 

Big Blue Island Chute 1974 

(Illinois River mile 57.5-58.9) 

Copperas Creek Lock 1978 

(Illinois River mile 136.7-136.9) 



Illinois Waterway Fish 19-7 



Location Year 

Treats Island 1979 

(Illinois River mile 279.3-280.0) 

Mississippi River Piasa Island Chute 1978 
(Mississippi River mile 207.5-209.0) 

Mississippi River Brickhouse Slough 1978 
(Mississippi River mile 207.8-209.0) 

A listing and description of all the stations is given in 
Appendix G, Table G-2, and the locations of the stations are 
shown in Figure 19-2. In considering locations for sampling, 
those that provide a desirable habitat for adult fish and a 
good distribution along the river were chosen. There are 
fewer stations in the upstream pools because of their short 
length . 

The stations are located most accurately by river mile. 
The river mile designation indicates the approximate area 
fished: for example, at the first electrof ishing station 
listed, the shoreline extending from the DuPage River mouth 
into Rapp's Boat Yard between river mile 276.8 and 277.8 was 
fished (Appendix G, Table H-2). 

Most of the stations were in side channels of the river 
and contained brushpiles, undercut banks, and holes where a 
variety of fish were expected to congregate. The five stations 
not in side channels were (1) the station above Pekin, where 
both sides of the main channel were fished; (2) the station 
along the shore of lower Peoria Lake; (3) the station in 
middle Peoria Lake, where docks and rip-rapping in various 
marinas were fished in the 1960's and where rip-rapping at a 
State conservation landing in Detweiller Park was fished in 
the 1970 's; (4) the station in the Des Plaines River, where 
the wide mouth of the DuPage River and a boat yard were 
fished; and (5) the old lock at Copperas Creek. 

Minnow- seining . Illinois and Mississippi River minnow 
seine stations that were sampled in 1978 and 1979 are listed 
in Appendix G, Table G-2. The 1978 stations are shown in 
Figure 19-3. Thirty-six stations were sampled between 21 June 
and 22 August, 1978. Of those in the Illinois River, twenty- 
four were located in main channel border habitats, four in 
side channels, four in the only main channel lake on the Illi- 
nois River, Peoria Lake, and two in backwater lakes. The 
two Mississippi River stations included a main channel border 
station and a side channel station. In 1979, thirty-one 
stations were sampled between 22 June and 15 August. All of 



Illinois Waterway Fish 



19-8 



ILLINOIS WATERWAY 
EUCIROFISHING STATIONS 




1 

1 







25 




50 


1 






MILES 



















50 










KILOMETERS 









OF 


PROXIMATE LIMITS 
DRAINAGE BASIN 







MISSOURI ^oc. i 

ST. LOU I 



O = CITIES 

. = L%Ct. AND DAM SITES 
• ' MAIN CHANNEL BORDER STSTION 
®= IAIN STEM UKE STATION 

■ = SIDE CHANNEL STATION 



Figure lD-2. Illinois Waterway electrof ishing stations, 1978- 
1979. The Mississippi River station on the map 
actually consisted of 2 side channel stations 
on opposite sides of the main channel at the 
same river mile (see Appendix rj , Table C-Z ) . 



Illinois Waterway Fish 



19-9 



ILLINOIS WATERWAY 
1978 MINNOW SEINE STATIONS 




/ 


25 50 


1 


MILES 


1 1 


1 







50 


KILONETESS 


= APPROXIn* 

OF DRAIW 


ITE LIMITS 
iGL BASIN 


O = cniEs 




m = LOCK AND 


DAf, SITES 


• = MAfN CHANh 


lEL BORDER STATION 


® = MAIN STEM 


LAKE STATION 


■ = SIDE CHANr 


lEL STATION 


A ' FLOOD PLAI 


N LAKE STATION 



Figure 19-3. Illinois Waterway minnow seine stations, 1978. 
Some of these stations were deleted and others 
added in 1979 as explained in the text and 
summarized in Appendix G, Table G- 2 . "Flood 
Plain Lake stations" are synonymous with 
bottomland or backwater lake stations in the 
text and Table G-2. 



Illinois Waterway Fish 19-10 



these stations were on the Illinois River: twenty-five 
in main channel border habitats, two in side channels, 
and four in Peoria Lake. 

In order to obtain information on what small fish 
species occur in the river (occurrence) , collections were 
made from all of the habitat types identified above. Time 
and manpower constraints, however, mandated that in order to 
assess the longitudinal distribution of small fishes along 
the river, intensive sampling of one particular habitat type 
at different river miles was necessary. As a result, the 
emphasis during the 1978-1979 minnow seine program was placed 
on main channel border habitats. Major changes in station 
selection between 1978 and 1979 were: a) the deletion of 
the Mississippi River stations in order to more intensively 
sample in areas further upstream which are expected to be 
affected to a greater extent by increased diversion, and b) 
the deletion of the backwater lake stations because these 
habitats were so broad that they could not be effectively 
sampled (in the given time schedule) to yield results that 
we could quantitatively relate to other areas with confi- 
dence . 

Hoopnetting . Eight Illinois River hoopnetting stations 
were sampled between September, 1978 and December, 1978 
(Appendix G, Table G-2, Figure 19-4), These stations (six 
main channel border stations and two side channel stations) 
were selected a) to develop standard techniques to be used 
in 1979, and b) to match as nearly as possible stations 
used by previous researchers. The dates on which the 1978 
stations were sampled, however, could not always be matched 
to previous studies. The thirty-six hoopnetting stations 
sampled in 19 79 (Appendix G, Table G-2, Figure 19-4) included 
sixteen main channel border stations, thirteen side channel 
stations, five backwater lake stations, one main channel 
station and one slough station. In 1979, both the hoopnetting 
station location and sampling dates were established primarily 
to match those used by previous researchers. 



Methods 

Chicago-Area Reaches 

Various methods were used during the 1976 Northeastern 
Illinois Planning Commission fish inventory. These included 
boat and backpack electrof ishing , seining and dip-netting. 
Detailed descriptions of these methods can be found in Dennison 
(1978) . 



Illinois Waterway Fish 



19-11 



ILLINOIS KATERHAY 
1978-1979 HOOP NETTING STATIONS 




— 


OF DRAINAGE BASIN 


o 


CITIES 


+ 


LOO AND DAn SITES 


• 


MAIN CHANNEL BORDER STATIONS 


® 


MIH STEM LAKE STATIONS 


■ 


SIDE CHANNEL STATIONS 


▲ 


FLOOD PLAIN LAKE STATIONS 


B 


SLOUGH 



Figure 19-4. Illinois Watervav lf^78 and 1979 Hoopnettinp 
Station. "Flood Plain Lake stations" are 
synonymous with bottomland or backwater lake 
stations in the text and Table H-Z. 



Illinois Waterway Fish 19-12 



The fish species of the area were evaluated according 
to the degree of habitat modification they could tolerate. 
Adaptable species which could survive in a degraded habitat 
were considered tolerant. The two other categories, moder- 
ately tolerant and intolerant, show decreasing amounts of 
adaptability. Pflieger (1975) and Smith (1979) provided 
life history data for these evaluations. 

Illinois River 

Electrof ishing . In order to sample under similar 
environmental conditions each year, electrof ishing was usually 
conducted from late August to mid-October, but only when the 
river was at pool stage behind the navigation dams. All 
stations could not be fished every year because of high water 
levels; no stations were sampled in 1971 and 1972. In 1977, 
the river above mile 113 was not sampled because water levels 
were high. 

Fish were stunned by an electric current produced by a 
230 volt, 180 cycles/sec, AC generator (Homelite 9HY-1), and 
transmitted through the water via 3 cables suspended from 
booms in the front of an 18-ft aluminum boat. Electrof ishing 
was conducted in 15-minute segments, and a total of 60 minutes 
was spent electrof ishing at most stations. In small side 
channels, or where an abundance of fish was collected quickly, 
only 30 minutes were spent electrof ishing . 

The stunned fish were dipped from the water and placed 
in plastic garbage cans containing water. Fish were identified, 
counted, weighed, checked for disease, and returned to the river 
The few fish that died were buried on shore. 

There are problems associated with any sampling technique, 
including electrof ishing . In a turbid river such as the 
Illinois, fish must be within a few inches of the surface to 
be seen and netted. Bottom- dwelling species such as catfish 
and bullhead do not always surface when shocked, and they are 
underrepresented in electrof ishing catches. Gars, such as 
the short-nose gar, and bigmouth buffalo are not as vulner- 
able to electric shock as other species, such as sunfish. 
Gizzard shad are often only momentarily stunned and occur in 
such large numbers that it is impossible to net them all before 
they recover. Since the electrof ishing program was designed 
to sample populations of adult fish, dip nets of 1/4-inch 
mesh size were used; hence, small fish such as minnows often 
were not retained in the nets. In addition, electrof ishing 
was conducted only in areas that were connected to the river 
at all times of the year, so that species occurring primarily 
in lateral lakes which were either permanently or inter- 
mittently cut off from the river were not represented or 
were underrepresented in electrof ishing collections. 



Illinois Waterway Fish 19-13 



Mi nnoK- seining . At least 4 minnow- seine hauls were 
made at each station with a 20' x 4', l/8"-mesh, light- 
brown "Common Sense" seine. Each haul covered a distance of 
approximately 15 paces made in the downstream direction. 
All fish collected were preserved in 101. Formalin and returned 
to the River Research Lab at Havana for identification. 
Dr. L. Page and Dr. P. Smith of the Faunistics Section, 
Illinois Natural History Survey, assisted in the identi- 
fication of extremely small or otherwise difficult specimens. . 

In 1978, minnow-seine stations were sampled generally 
in the upstream direction beginning in the Alton Pool. A 
preliminary analysis of the 1978 data from main channel 
border stations showed that this might produce a bias in 
assessing species distribution along the river if certain 
species of fish moved from shallow-water habitats in mid- 
summer, to deep-water habitats in late summer. As an example, 
the numbers of gizzard shad in our minnow-seine catch 
decreased late in the summer while sampling in the upper 
Illinois River, but we were not sure if this was due to a 
change in species distribution or a change in habitat 
preference from mid to late summer. As a result, the 1979 
minnow-seine stations were not sampled sequentially from one 
end of the river to another, but rather in three phases, 
each covering the length of the river. 

Hoopnetting . Hoopnetting was conducted with hoopnets 
having 1 l/2"-mesh netting on the front 3 hoops and l"-mesh 
netting on the rear 4 hoops. Wings and leads were used only 
in backwater lake stations. The nets were set with the open 
ends facing downstream (except at backvs-ater lake stations) for 
48-hr periods. Identification and measurements were made 
immediately in the field. 

Results 



The results of all of the methods used to assess the 
existing Illinois Waterways fishing are presented here. Com- 
prehensive tables covering the entire waterway are presented 
first, followed by more detailed results that relate to the 
Chicago-area and Illinois River reaches. 

Illinois Waterway Comprehensive Results 

The potential fish fauna of the Illinois Waterway includes 
150 fish species, carp x goldfish hybrids, and various other 
hybrids (Appendix C, Table C-12). These species either have 
been collected recently or are likely to occur in the watenvay. 



Illinois Waterway 19-14 



Species are considered likely to occur when 1) they are 
collected in the main diversion waterway in the past but not 
since 19S0; 2) they were collected recently only in adjacent 
waterways and/or Lake Michigan but should also occur in the 
main diversion waterway; 3) they were collected recently only 
in the adjacent waters and/or Lake Michigan but could occa- 
sionally stray into the main diversion waterway. 

In order to initially present a comprehensive picture of 
the entire waterway's fish populations, Tables 19-2 and 19-3 
were prepared. Table 19-2 indicates the known occurrence and 
relative abundance of each fish species by waterway reach. 
The supportive data for Table 19-2 is contained in Appendix 
G, Tables G-3 through G-34 except for references regarding 
species occurrences taken from sources other than the North- 
eastern Illinois Planning Commission Fish Survey and recent 
Illinois Natural History Survey fish sampling programs. 

The criteria used in defining the terms abundant, common, 
uncommon, rare and presumed extirpated for the Chicago-area 
reaches were as follows: 

A = Abundant, readily observed. Abundant species 
generally were represented by more than 20 
individuals and were present in all or most 
samples from a waterway subdivision. 

C = Common, usually readily observed. Common species 
generally were represented by more than 10, but 
less than 20, individuals. They may have been 
taken from all sites in a waterway subdivision. 
Five to 10 individuals from each of nearly all 
sites in a waterway subdivision, however, would 
result in a species being designated as common. 

U = Uncommon, but likely to be observed. Uncommon 
species generally were represented by more than 
two, but less than 10 individuals. They usually 
were present from only a few sites in a waterway 
subdivision. One or two individuals from each of 
several sites within a waterway subdivision, however, 
would result in a species being designated as 
uncommon . 

R = Rare, within the range of the species, but seldom 
observed. Rare species usually were represented 
by only one or two individuals and from only one 
or two sites in a waterway subdivision. 

E = Presumed extirpated, known only from collections 
made prior to 1905. 



Illinois Waterway ^ish 



19- IS 



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Illinois Waterwav ^ish 



19-16 



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19-20 





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19-21 





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Illinois Waterway Fish 



19-22 





>13AIM IddlSSISSUM 






































Tood Nonv 




ex 








u 
























M3AIH SIONmi H3.<l\01 




IV 


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Pi 




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lOOd 






u 


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CC 


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Qi 








Di 










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Illinois Waterway Fish 



19-23 



H3A1M IddlSSlSSlW 
TOOd NOXTV 



a3AIH SlOSmi >J3.V\OT 
TOOd NOXIV 



lOOd 
30NVHOVT 



TOOd 

viHoad 



pj :d 



Oi u 



TOOd 
>iDOH QHAHVIS 



TOOd 
S3ni3SHVW 



TOOd 
QNVTSl N3aS3Ha 



TOOd 
aVOH NOaNVMH 



T3NNVHD 

ovs xawmvD 



H3Aiy 
xswmvo 3Txxn 



M3AIH 

X3l\mV3 



TVNVO dIHS QNV 
AHVXINVS OOV3IHD 



H3Aiy OOVDIH3 
HDNVaa HX.IOS 



>13AIH 
OOVDIHD 



u :=) 



H3AIH OOVDIHD 
HOKVMa HXMON 



T3NNVHD 
3HOHS HXaON 



SAVMH3XVA\ 
XN33VraV 



NVOIHDIW 
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Illinois Waterway Fish 



19-24 





H3AIM IddlSSlSSIW 






Di 3 












—1 


1=3 


=> 




o; 








lood Nonv 
































aa.MH sioMmi aaMOT 


Di 


CC 


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PC 


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lOOd NOilV 
































TOOd 


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w 


PC 


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cc 


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lOOd 

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Illinois Waterway Fish 



19-25 





H3AIM IddlSSISSIN 






























TOOd NOXTV 




























a^AIH SION'mi H3.WOT 




























>^ 


TOOd NOXTV 


Di 












DC 




a: Di 


Qi 


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d; d; 


TOOd 
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lOOd 




























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a 


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lOOd 




























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pj 








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D 


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d: 










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Illinois Waterwav Fish 



19-26 





H71AIM IddlSSISSIW 


':zi 


Di 








lOOd NOXIV 












H3AIH SlONjmi yaMOT 


:d 


UJ 








Tood Nonv 










TOOd 


u 


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nooJ 


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tu 






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H3AIW 










i,3wmvD 3nxin 










CO 

2 

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M3AIU 










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C/3 
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TVNV3 dIHS ONV 










AHVXINVS OOV3IHD 










Q 

23 












H3AI>1 ODVOIHD 










D 


Ho.s;vHa Hinos 










CO 












H3A1M 












OOVDIHD 




Di 






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It is difficult to compare the results of one sampling 
technique to another, electrof ishing to mi nnow- seining for 
instance, in terms of abundance, vdien large numbers of fish 
and sampling stations are involved and the techniques are 
differentially selective for certain species and typically 
used in different habitats. This was the case when we 
attempted to compile recent fish survey data from the Illinois 
River reaches of the Waterway (i.e., from the Dresden to the 
Alton Pools) into Table 19-2. This situation prevented us 
from developing simple quantitative descriptions (such as 
those described above) for defining abundant, common, and 
rare that would be useful for all of the combined results. 
It should be understood, therefore, that for the Illinois 
River reaches presented in Table 19-2, these terms were meant 
to be used as relative indicators of abundance rather than 
quantitative measures. 

Table 19-3 presents general occurrence and abundance 
information for each fish species by habitat. The habitats 
indicated, and their relative distribution throughout the 
waterway have been described in Chapter 15. This information 
can be helpful in estimating the impacts of increased diver- 
sion on aquatic populations through changes in habitat 
quality and quantity. 

C hicago-Area Reaches 

Since 1950, 47 species of fish, carp x goldfish hybrids, 
and various centrarchid hybrids have been collected from the 
Chicago Area Waterway reaches. The 1976 Metropolitan 
Sanitary District of Greater Chicago inventory included 40 
of these species (plus hybrids) from sites located on the diver- 
sion waterway. Lake Michigan collections added five species 
to this list. Those species not collected in 1976 were long- 
nose gar, skipiack herring, bigmouth buffalo, black buffalo, 
shorthead redhorse, yellow bullhead, brown bullhead, channel 
catfish, and white bass. 

Appendix G, Tables G-3 through G-12 contain fish collection 
data from stations located in Lake Michigan and in the Chicago- 
area waterway reaches. However, no table exists for the 
Brandon Road' Pool, which was not sampled in the 1976 inventory. 
These results, with the exception of the Lake Michigan stations 
which are beyond the scope of this report, will be described 
in detail later in the discussion section. 



Illinois River 

Electrofishing Catch . The elect rof ishing catch results 
over the period 1959- l5T9 are presented in Appendix G, G-30 to 



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Illinois Waterway Fish 



19-39 



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Illinois Waterway Fish 19-40 



G- 54. In addition, histograms covering both periods were 
prepared using individual fish species data for largemouth 
bass, white bass, channel catfish, carp, goldfish, and 
black bullhead. However, data from the two Mississippi 
River electrofishing stations in 1978 and 1979 were omitted 
from these histograms (Figures 19-6 through 19-11) because 
they were not sampled in previous years . The Copperas 
Creek Lock data were omitted from these histograms for the 
same reason and because a barge was anchored in the lock and 
a dredge boat was operating beside it in 1979. 

Minnow seine Catch . Minnow seine catch results from 
the Illinois River in 1978 are presented by pool in Appendix 
G, Tables G- 15 through G-18. Similarly, the 1979 results 
are presented in Appendix G, Tables G- 19 through G-24. The 
information in these tables was summarized by year in Tables 
19-4 and 19-5, which show for each pool: the number of hauls 
made, the number of species caught, the total number of fish 
caught per haul, the major species (those that made up at 
least 31 of the pool catch) caught, and their relative abun- 
dance (measured as % of the pool catch) . Species making up 
less than 5% of each minnow-seine pool catch were omitted 
from Table 19-4 not only for brevity, but also because 
results compiled from such low numbers of fish can often be 
biased if a school of a particular species was present at 
or near the sampling site. 

Hoopnetting Catch . Hoopnetting results from 1978 and 
1979 are combined in this report since only 8 stations (out of 
the two-year total of 44) were sampled in 1978. The hoop- 
netting data are presented in Appendix G, Tables G- 25 through 
G- 29. A summary of these data is presented in Table 19-6. 



Discussion 

Chicago-Area Reaches 

North Shore Channel . The North Shore Channel is an 
inlet for Lake Michigan diversion and, therefore, the diver- 
sity of the channel's fishery is influenced by the lake species 

The 1976 Metropolitan Sanitary District of Greater 
Chicago inventory included collections from three sites on 
the channel. Twelve fish species and two hybrids, carp x gold- 
fish and green sunfish x pumpkinseed, were taken from the 
Waterway (Table G-4). Lake Michigan species (alewife, 
ninespine stickleback, rainbow smelt, spottail shiners and 
yellow perch) represented less than 201 of the total number 
of fishes collected. Bluntnose minnow was the most abundant 
species in the collections, representing 53% of the total 



Illinois Watervav Fish 19-41 



Table 19-4 



ILLINOIS RIVER 
MINNOW SEINE SU^IMARY (19 7 8) 







Total 


No. 


No. 


Fish 


of 


of 


Per 


Hauls 


Spp. 


Haul 



a ° °^ 

Major Species Catch 

Dresden Pool 4 4 15 Bluntnose minnow 60 

Fathead minnow 20 

Carp 15 

Emerald shiner 5 

Marseilles 8 7 6 
Pool 



Starved Rock 8 10 21 
Pool 



Peoria Pool^ 44 35 100 



LaGrange PooP 48 45 90 



Alton Pool 32 37 100 



Bluntnose minnow 


45 


Spottail shiner 


18 


Emerald shiner 


16 


Sand shiner 


12 


Green sunfish 


6 


Emerald shiner 


6 5 


Bluntnose minnow 


19 


Sand shiner 


6 


Spotfin shiner 


4 


Emerald shiner 


71 


Spottail shiner 


15 


Gizzard shad 


4 


Emerald shiner 


3 5 


Gizzard shad 


2 5 


Bluegill 


11 


White bass 


4 


Spottail shiner 


4 


Broolc silversides 


3 


Gizzard shad 


81 


Drum 


5 


Emerald shiner 


3 



^Those species making up at least 31, of the Pool catch 
Including bottomland lake habitats. 



Illinois Waterway Fish 



19-42 



Table 19-5 



ILLINOIS RI\^R 

MINNOW SEINE SWT^'ARY (19 79) 







Avg # 




No. 


No. 


Fish 




of 


of 


Per 




Hauls 


Spp. 


Haul 


Major Species^ 



Dresden Pool 



Marseilles 
Pool 



Starved Rock 
Pool 



8 7 21 Carp 

Bluntnose minnov 
Emerald shiner 
Gizzard shad 

12 22 62 Spottail shiner 

Emerald shiner 
Gizzard shad 
Bluntnose minnow 
White crappie 
Skipjack herring 
Spotfin shiner 

8 17 40 Emerald shiner 

Bluntnose minnow 
Striped shiner 
Sand shiner 
Spottail shiner 



Peoria Pool ^ 32 31 



LaGrange Pool ° 28 25 



Alton Pool 



34 Emerald shiner 
Spottail shiner 
Gizzard shad 
Skipjack herring 

77 Gizzard shad 

Emerald shiner 
Spottail shiner 
White bass 



28 25 32 Emerald shiner 

Gizzard shad 
Carp 

V.'hite bass 
Black crappie 



% of 
Catch 

66 

23 

5 

4 

28 
25 
12 
10 

7 
5 
3 

42 

28 

7 

4 

4 

33 

31 

22 

4 

53 

27 

q 

5 

40 

35 

4 

4 

4 



^ Those species making up at least 3% of the Pool catch. 
D No bottomland lake habitats sampled this year. 



Illinois Waterway Fish 



19-43 



Table 19-6 



ILLINOIS RIVER 
HOOPNETTINH Sl'^T^iAPY (19 7 8 f-, 79) 





No. 




Total 








of 


No. 


No. of 




% of 




Net 


of 


Fish per 




Total 




Davs 


Spp . 


Net Dav 


*'aior Species ^ 


Catch 


Marseilles 


26 


20 


15 


Carp 


4 5 


Pool 








Ouillback 
River carpsucker 
Black bullhead 
Yellow bullhead 
Channel catfish 
Black crappie 


16 

7 
7 
5 
4 
4 


'^t-rvcd 


56 


22 


12 


Carp 


28 


Rock 








River carpsucker 


21 


Pool 








Channel catfish 
Ouillback 


16 
11 



Black crappie 
Yellow bullhead 



Peoria 
Pool 



133 32 23 River carpsucker 

Ouillback 
Vv'hite bass 
Carp 
Cizzard shad 



3? 
21 
12 

in 

7 



LaGrange 
Pool 



118 



27 



River carpsucker 

Oizzard shad 

freshwater drum 

Carp 

Black cra-npie 

Ouillback' 

Wh i t e bass 

Channel catfish 



18 

17 

16 

IS 

6 

6 

5 

3 



Sheet 1 of 2 



Illinois Waterway Fish 19-44 

Table 19-6 concluded -- 1978-79 Hoopncttinp Suirirarv 



No. 




Total 






of 


No. 


No. of 




% of 


Net 


of 


T^ish Per 




Total 


Davs 


Snp . 


Net Dav 


^'aior Species ^ 


Catch 


128 


26 


10 


rizzard shad 

BlacV crappie 

Ouillback 

^reshvater drup. 

Bluepill 

Carp 

Piver carrsucV'er 

V.'hite bass 

V.'hite crappie 


25 
20 
10 
8 
7 
5 
4 
4 
3 



• 

I 



^Those species making up at least 3^^ of the Pool catch 



Sheet 2 of 



1 



Illinois Waterway Fish 19-45 



number collected. All of the lake species are classified 
as intolerant and these were the only intolerant fishes col- 
lected. The majority of those river species present were 
highly tolerant to habitat abuse. Illinois Natural History 
Survey records indicate rock bass and golden shiners are 
present in this area (Table 19-2). It is highly probable 
that these species still exist in the cahnnel near the lake. 

The good-quality fishery at the mouth of the North 
Shore Channel basically is the result of diversion waters. 
Collections here included a diverse population of lake and 
river species. Collections from the remainder of the channel 
indicate an extremely poor fishery, consisting almost 
entirely of carp, goldfish, and carp x goldfish hybrids. 

North Branch of the Chicago River . The segment of the 
North Branch of the Chicago River which receives and trans- 
ports diversion waters is influenced primarily by the fisheries 
present in the Chicago River, the lower portion of the North 
Shore Channel, and the North Branch upstream from its con- 
fluence with the North Shore Channel, 

The Metropolitan Sanitary District of Greater Chicago 
sampled three sites on the North Branch during the 1976 
inventory. Two attempts to collect at site 56 failed to 
secure fishes. The collection from station 55 included only 
four species, each represented by a single specimen, and 
carp X goldfish hybrids (Appendix G, Table G- 5) . These 
species are all considered tolerant to habitat abuse. Site 
67 was located at the confluence of the Chicago River and its 
North and South Branches. This collection consisted of four 
species of ecologically tolerant river fishes; alewife, an 
intolerant lake species; and carp x goldfish hybrids. Illi- 
nois Natural History Survey records indicate an additional 
five species in the North Branch which apparently are now 
extirpated (Table 19-2). 

Data from the North Branch of the Chicago River indicate 
the present fishery is extremely poor. Only half of the col- 
lections in the area resulted in fish being collected, and 
these collections yielded only eight species. The effect of 
Lake Michigan diversion is evident in the appearance of alewife 
in the collection at the North/South Branch junction site. 

Chicago River . The Chicago River represents the major 
inlet of Lake Michigan water into the Illinois Waterway. As 
would be expected, the diversity of the river's fishery is 
increased by the presence of Lake Michigan fish species. 

The Metropolitan Sanitary District of Greater Chicago 
collected at one site in the river during the 1976 inventorv'. 
This collection included 14 species of fish and carp x goldfish 



Illinois Waterway Fish 19-46 



hybrids (Appendix G, Table G-6). The collection was a mix- 
ture of moderately to highly tolerant river species and intol- 
erant Lake Michigan species. The lake species, alewife, 
ninespine stickleback, and rock bass, represented 48°b of the 
total number of fish collected. The Illinois Natural History 
Survey records indicate an additional seven species in the 
area which are now presumed extirpated (Table 19-2). 

The Chicago River contains primarily a good-quality 
fishery. This quality is almost exclusively the result of 
the abundance of Lake Michigan species. River species, 
which require a higher quality environment, possibly could 
exist in this area if introduced there. The degraded 
condition of the intervening watersheds precludes their 
movement . 

South Branch of the Chicago River . The diversity of the 
fishery of the South Branch of the Chicago River is directly 
influenced by the North Branch and Chicago River fisheries. 
Also, Lake Michigan species may enter this area. 

The Metropolitan Sanitary District of Greater Chicago 
did not collect specifically in the South Branch river section. 
A collection from an adjacent site located at the junction of 
the Chicago River and its North and South Branches reflect 
the fish fauna of the South Branch sufficiently to be used 
to evaluate the present fishery of the South Branch. This 
collection consisted of four species of ecologically tolerant 
river fishes; alewife, an intolerant lake species; and carp x 
goldfish hybrids (Appendix G, Table G-7). Illinois Natural 
History Survey records indicate Johnny darters were once 
present in this river section, but they are now presumed to 
be extirpated (Table 19-2). 

A poor-quality fishery presently exists in the South 
Branch of the Chicago River. The collection was dominated 
basically by tolerant river species, carp and goldfish, but 
alewife also were present. The occurrence of alewife indi- 
cates the presence of an effect of diversion waters from 
Lake Michigan, at least in the Northernmost portion of 
the South Branch. 

Chicago Sanitary and Ship Canal . The Chicago Sanitary 
and Ship Canal is the major waterway carrying diversion waters 
in the Chicago area. The canal carries water diverted into 
the North Shore Channel and Chicago River. Also, water diverted 
through the O'Brien Locks will enter the canal via the Calumet- 
Sag Channel. 

The Metropolitan Sanitary District of Greater Chicago 
collected at four sites in the Sanitary and Ship Canal 
during their 1976 inventory. Site 68 was sampled seven times. 



Illinois Waterway Fish 19-47 



two of which were successful, and site 50 was collected 
three times, once successfully. The collections included 
eight species of fishes (Appendix G, Table G08) , almost 
all of which are considered highly tolerant to habitat 
abuse, and carp x goldfish hybrids. Goldfish was the most 
abundant species in the canal, representing 48 % of the total 
number of fishes collected. Two alewife were taken at site 
48, representing the maximum penetration inland of Lake 
Michigan species. Illinois Natural History Survey records 
indicated no additional species in this area. 

The Chicago Sanitary and Ship Canal contains an ex- 
tremely poor fishery. Less than half of the 1976 collections 
attempted in this area yielded fishes, and those successful 
collections included few species taken in low numbers. 

Calumet River . The Calumet River is an inlet for Lake 
Michigan diveision, and, therefore, the diversity of the river's 
fishery is influenced by lake species. In addition, an 
inlet to Lake Calumet produces a lake-like habitat re- 
sulting in lake species potentially entering the river. 

The Metropolitan Sanitary District of Greater Chicago 
1976 inventory collections from three sites in the river 
included 11 fish species (Appendix G, Table G -9) . The col- 
lections consisted of moderately to highly tolerant river 
species and intolerant lake species, the latter representing 
less than 101) of the total number collected. Alewife and 
yellow perch were collected near O'Brien Locks, indicating 
that lake species are capable of surviving throughout this 
subdivision. Twenty additional species have been collected 
from this area according to Illinois Natural History Survey 
data (Table 1902). Of these, 14 are presumed extirpated. 

The quality of the Calumet River fishery appears to 
be very good. Lake Michigan species not only exist near 
the mouth of the river but also penetrate inland to near 
the locks at the southern end of "the waterway. The lotic 
habitat created by the Lake Calumet inlet could possibly 
explain the large population of largemouth bass which exists 
in the waterway. 

Little Calumet River. The Little Calumet River receives 
water diverted through the O'Brien Locks and carries it in- 
land to the Calumet-Sag Channel. The river's fishery is 
potentially influenced by the species present in Lake ^Uchi- 
gan, Calumet River, Grand Calumet River, and Lake Calumet. The 
degree of input from Lake Michigan, Calumet River and Lake 
Calumet depends on the amount O'Brien Locks is utilized for 
ship traffic. 



Illinois Waterway Fish 19-48 



Fish collections were secured from three sites by the 
Metropolitan Sanitary District of Greater Chicago in 1976. 
Eleven fish species and carp x goldfish hybrids were taken 
in these collections (Appendix G, Table G-10). All of these 
species are considered highly tolerant to habitat abuse. 
Green sunfish and gizzard shad were the most abundant species 
in the collections, representing 56"6 of the total number of 
fishes. Illinois Natural History Survey records indicate 
that northern pike were collected from these waters prior 
to 1905 (Table 19-2). They are presumed extirpated at this 
time . 

Fishery quality in this segment of the Little Calumet 
River is poor. The collections were dominated by tolerant 
fish species taken in limited numbers. Collections made in 
1976 approximately 10.5 miles inland from Lake Michigan in 
the Grand Calumet River, which has a direct influence on the 
Little Calumet's fishery, were entirely unsuccessful. 

Calumet-Sag Channel . The Calumet-Sag Channel directs the 
diverted water from the O'Brien Locks into the Chicago Sani- 
tary and Ship Canal. The channel has three major tributaries, 
Mill Creek, Stony Creek, and Tinley Creek. The Illinois- 
Michigan Canal bisects the Calumet-Sag Channel near its junc- 
tionwith the Sanitary and Ship Canal. The Calumet-Sag Channel 
originates at the Little Calumet River; hence this river would 
have an influence on the diversity of fishes in the channel. 

The 1976 Metropolitan Sanitary District of Greater 
Chicago inventory included collections from ten sites in 
the Calumet-Sag Channel basin. Only four sites are actually 
in the channel. 

The 1976 inventory included 11 fish species and two 
hybrids, carp x goldfish and green sunfish x pumpkinseed 
(Appendix G, Table G-11). The majority of the species are 
considered moderately to highly tolerant. One alewife was 
taken from this subdivision, indicating the relative extent 
inland that this Lake Michigan species survives. Illinois 
Natural History Survey records indicate that an additional 
three species have occurred in this reach (Table 19-2). 

Collections from the Calumet-Sag Channel were extremely 
poor, with two of three collections in the channel resulting 
in a total of only six fish. The fishery quality of the 
channel's tributaries was considered fair (Brigham et al. 1978) 
Collections from the 1 1 linois -Michigan Canal, Stony Creek, 
and Tinley Creek, summarized by Brigham et al. (1978), were 
slightly more diverse but consisted entirely of fishes showing 
some degree of tolerance to habitat abuse. The small collec- 
tion secured from Mill Creek most likely was due to the 
collecting method (electrof ishing with boat shocker). If 



Illinois Waterway Fish 19-49 



increased Lake Michigan diversion improves water quality in 
the Calumet-Sag Channel, it is possible that the channel's 
fishery will be supplemented by recoloni zation from the tribu- 
tary fish populations. 

Brandon Road Pool . The Des Plaines River merges with 
the Chicago Sanitary and Ship Canal and the 1 11 i nois -Mi chi gan 
Canal to form the Brandon Road Pool. No major tributaries 
Join this segment of the river. 

Fish collections were not secured from this area during 
the 1976 Metropolitan Sanitary District of Greater Chicago 
inventory. Collections in this area by the Illinois Natural 
History Survey also were limited. Illinois Natural History 
Survey records indicate that Iowa darters, fantail darters, 
and mottled sculpins were present prior to 1905 (Table 19-2). 

Dresden Island Pool . The fishery of the Dresden Island 
Pool, a segment of the lower Des Plaines, is influenced by 
Cedar Creek, DuPage River, Hickory Creek, Illinois and Michi- 
gan Canal, Jackson Creek, Kankakee River, Rock Run, and Sugar 
Run. 

The Metropolitan Sanitary District of Greater Chicago 
1976 inventory included fish collections from eight locations 
in this reach of the waterway. Since only one site was located 
in the main channel, data from sites at the mouths of princi- 
pal tributary streams are included to provide a better idea of 
the fishery. The majority of these sites were located in 
the mouths of various tributary streams, where water quality 
is essentially that of the river (Brigham et al. 1978). 
Two unsuccessful attempts to collect fish were made on Jackson 
Creek. The 1976 inventory secured 33 species, carp x goldfish 
hybrids, and three ccntrarchid hybrids from the area (Appendix 
G, Table G-12). The majority of these species show some degree 
of tolerance to habitat abuse. Seven of the species (horny- 
head chub, redfin shiner, northern hogsucker, black redhorse, 
stonecat, rock bass, and smallmouth bass) now present are 
considered intolerant to habitat abuse, but very few specimens 
of these were collected. Carp and green sunfish were the most 
abundant species in the watershed, representing 26-o and 18c, 
respectively, of the total number of fishes collected. Both 
of these species are highly tolerant of habitat abuse. Collec- 
tions by the Illinois Natural History Survey add 13 more specaes 
Table 19-2 indicates the relative abundance of these species 
from this area. 

Fishery quality in this main-channel portion of the Des 
Plaines River drainage system is considered fair. The 1976 
collections indicate Sugar Run and DuPage River provide good 
fishery input into the river system. Jackson Creek does con- 
tain a good fishery in its upper regions, but at its junc- 



Illinois Waterway Fish 19-50 



tion with the lower Des Plaines, the fishery quality has been 
reduced to poor. Hickory Creek also contains a good-to-high 
quality fishery, but its fishery is reduced to fair at the 
junction. The Kankakee River has the best influence upon the 
pool's fishery. Ongoing collections by the Illinois Natural 
History Survey have included 63 species from the Kankakee 
basin. One-third of these species are considered to be eco- 
logically intolerant. Thus, the Kankakee River is considered 
to have an excellent assemblage of species which potentially 
could enter this segment of the diversion waterway (Brigham 
et al. 1978) . 

Apparent Effect of Present Diversion 

The effect of the present diversion on the upper Illinois 
Waterway is confined primarily to the three intake points and 
the downstream waters adjacent to them. At the intake points, 
good quality water is withdrawn from Lake Michigan at a vol- 
ume sufficient to create a distinct transitional habitat 
(Figure 19-5) . This transitional habitat has the physical 
characteristics of a channel (flow, shallow depth, elongate 
morphometry) but sustains a fishery consisting of some lake 
species as well as river fish species. The transitional zone 
on the North Shore Channel and Chicago River reaches only a 
short distance inland before deteriorating water quality 
precludes the survival of lake species. 

The presence of lake species in the Calumet River indi- 
cates the presence of transitional habitat downstream to the 
T.J. O'Brien Lock. Transitional habitat is not evident 
inland from the lock. This is due primarily to the heavy 
loading of toxic substances into the waterway. 

One lake species, the alewife, was collected near the 
junction of the Little Calumet River and the Calumet-Sag 
Channel. Though few fish of this species were taken, their 
presence serves to indicate a relative maximum penetration 
inland for lake species (Figure 19-5). This zone would con- 
tinually vary in length relative to the volume of diversion 
in the channels and to the toxicity of channel waters. 
The diversion waters have little effect on the fisheries 
of the upper Illinois Watenvay past the point of maximum 
penetration inland of the alewife. 

Chicago Area 

The present condition of the aquatic habitat in the 
upper Illinois Watei~way is generally poor (Figure 19-6). 
The 1976 Metropolitan Sanitary District of Greater Chicago 
inventory secured only 40 fish species from 28 sites located 



Upper Waten\-ay Fish 



19-51 




Figure 19-5. Effect of present diversion on upper Illinois 
Waterway, Cook, DuPage, and Kill Counties, 
Illinois (transitional habitat (coarse dots) 
characterized bv high percentage of Lake 
Michigan species; maxiinum penetration inland 
(fine dots) of species characteristic of Lake 
Michigan) . 



Upper l\'aterv,ay Fish 



19-52 




Figure 19-6. Surr.n.ary of environir.ertal quality, upper Illinois 
Katervay, Cool;, DuPage, and Will Counties, 
Illinois (fine dots, good environmental qualitv: 
medium dots, fair environmental quality; coarse 
dots, poor environmental quality). 



Illinois Waterway Fish 19-53 



along the waterway. This is less than one- third of the 
number of species formerly occurring in northeastern Illi- 
nois. In addition, much of the diversity seen in the 1976 
inventory was due to collections from sites located at the 
mouths of tributaries and sites located adjacent to Lake 
Michigan. These sites usually were more diverse and included 
many minnow and lake species. 

The species collected most abundantly from the upper 
Illinois Waterway in 1976 was the carp. This species was 
collected from almost all of the upper Illinois diversion 
watersheds and also was collected frequently from the adja- 
cent waterways and Lake Michigan. Other species found in 
large numbers were bluntnose minnow, green sunfish, and 
goldfish. All of the dominant species of the upper Illinois 
Waterway are considered highly tolerant to habitat abuse. 

The abundance of carp and other tolerant species in 
the diversion waterway is a result of the poor quality of 
aquatic habitat. The Waterway consists primarily of 
man-made channels and channelized rivers. The substrate 
of the channels is composed predominantly of soft, anaerobic 
sediments (see Chapter 18). Water quality analysis during 
1976 indicated toxic concentrations of ammonia- nitrogen , 
cyanide, fluoride, iron (total), MBAS , and silver exist in 
the channels (Brigham et al. 1978). 

In this portion of the diversion waterway, the main 
channel and channel border (the most extensive habitats) 
contain a very poor fish fauna due to their degraded state. 
Also, the upper Waterway is devoid of bottomland lakes and 
sloughs, and nearly devoid of mainstem lake, side channel, 
and tailwater habitats. This places the burden of the upper 
Waterway fishery almost entirely on the tributary creeks 
and rivers. These are the areas which provide habitat for 
breeding and spawining of the natural fish fauna. 

Illinois River- General 

Before entering our detailed discussion of fish popu- 
lations in the Illinois River, we should emphasize that in 
a major river the size of the Illinois, fish sampling surveys 
provide only an estimate of relative abundances of fish species 
rather than quantitative measurements of actual populations. 
For this reason, we will often refer to the electrof ishing 
catch of largemouth bass, for instance, in a certain river 
reach, rather than the population of largemouth bass in that 
reach . 



Illinois Waterway Fish 19-54 



It should also be noted that scientific fish sampling 
surveys are not the only means of estimating the current 
status of fish populations in the river. For the Illinois 
River, in particular, we have found it useful to evaluate how 
the existing commercial fish harvest compares to that of the 
past. Figure 19-7, which was compiled using data from Starrett 
(1972:147), Bellrose et al . (1977:C-108, 109), and Forbes 
and Richardson (1919), shows how the commercial harvest of 
fish from the river steadily declined since the turn of the 
century. Unfortunately, while much of this decline can 
probably be related to decreasing commercial fish populations, 
we have no way of determining how much of this decline is 
due to changes in the declining economic value of commercial 
fishing on the decrease over the same time period in the 
number of commercially licensed fishermen operating on the 
river. We are sure, however, that the decline could not 
have been caused solely by economic factors because the 
commercial fishery on the Mississippi River has been relatively 
constant from 1950 through 1978 (Sparks 1977:42). A detailed 
discussion of the variety of factors that may have been 
related to the decline of the commercial fishery in the Illi- 
nois River was included in Bellrose et al . (19 77:107-115). 
Regardless of the causes, however, the commercial fish 
populations in the river have probably decreased substantially 
since the turn of the century. 

Following are separate discussions of the existing aquatic 
habitats and fish populations in three reaches of the Illinois 
River: the upper river (Dresden, Marseilles and Starved 
Rock Pools), the middle river (Peoria and LaHrange Pools), 
and the lower river (Alton Pool) . The discussion of the lower 
river also includes the results of sampling done in the 
Mississippi River reach of the Alton Pool. This breakdown 
of the Illinois River into three reaches resulted from the 
major morphological, hydrological and aquatic habitat differ- 
ences that exist between them. I 

The Upper Illinois River | 

The upper Illinois River is composed of a short reach 
of the Dresden Island Pool (the remainder of which is techni- 
cally in the Des Plaines River), the Marseilles Pool, and 
the Starved Rock Pool. These pools occupy a geologically 
young channel which has a steeper gradient, a narrower 
width, and generally firmer substrates than the middle and 
lower river. They are primarily composed of main channel 
and main channel border habitats, but side channel habitats 
increase throughout this reach in the downstream direction 
and small tail water areas exist in each pool. Few bottom- 
land lake habitats exist in these pools, particularly rela- 
tive to the middle Illinois River. Tributaries along this 
reach play an important role in supporting its fish popu- 
lations . 



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Illinois Waterv,'av Fish 19-56 



Dresden Pool . Although the Dresden Pool has already 
been discussed in terms of the Metropolitan Sanitary District 
of Greater Chicago fish sampling program conducted in the 
pool in 1976, additional information is available from 
Illinois Natural History Survey sampling data described 
below . 

The Dresden Pool is 14.5 miles long. Thirteen of these 
river miles are technically in the Des Plaines River. Approxi- 
mately 1.5 miles above the Dresden Lock and Dam, the Kankakee 
River joins the Des Plaines to form the beginning of the 
Illinois River. Most of this pool is made up of main channel 
and main channel border aquatic habitats (Table 15-1). A 
broad expanse of shallow water exists along the main channel 
where the Du Page River enters the Des Plaines, and one 
small side channel (at Treats Island) exists in the pool. 
Several tributaries enter the pool and probably influence 
its fish populations (see earlier discussion of Chicago- 
area waterway reaches) . 

The substrates of the pool are variable, but according 
to Butts (1974) they can generally be described as being 
"a thick, black fibrous muck having either an oily or musty 
smell". Many of the sediment samples obtained by Butts in 
the Dresden Pool in 1971 were highly infested with sludge 
worms and contained hea\y oil or petroleum products (Butts, 
1974:12). Most of the samples exerted a substantial oxygen 
demand. The presence of rock bottoms occasionally prevented 
Butts from obtaining samples in the pool (Butts, 1974:25). 

In 1978 and 1979, several stands of unidentified emer- 
gent aquatic plants were observed in the main channel border 
and side channel habitats of the pool. Unfortunately, we 
cannot comment on the recent history of these plant beds since 
regular observations in these areas were not made earlier. 

Historically, the primary limiting factor on fish 
populations in the Dresden Pool has been water quality (low 
dissolved oxygen and high toxicant concentrations) . The 
beneficial water quality impacts that the Kankakee River 
has on the pool is limited to the 1.5 mile reach downstream 
of its confluence with the Des Plaines River. 

Carp, goldfish, carp x goldfish hybrids, gizzard shad and 
green sunfish dominated the electrof ishing catch from the 
single Dresden Pool electrofishing station between 1959 
and 1974 (Table G- 2) . This station included main channel 
border habitats characterized by soft bottoms and submerged 
stumps where the Du Page River entered the Des Plaines River 
and also rip-rapped shorelines and pilings in a nearby 
marina. The presence of these species in the pool is probably 



\ 



Illinois Waterway Fish 19-57 



related less to the aquatic habitat conditions of the pool 
than it is to their ability to tolerate poor water quality 
conditions. A side channel habitat that was electrof ished 
only in 1979 and not in earlier years (Treats Island, 
river mile 279.3-280.0, Table G- 2) also yielded mostly carp 
and goldfish. Goldfish have historically been taken more 
in the upper Illinois River than in the middle or lower 
reaches (Figure 19-8), but their lower electrof ishing catch 
rates in the 1970 's may be related to improved water quality 
conditions in the upper river that have been created by a 
combination of high flows and improved waste treatment by 
the Metropolitan Sanitary District of Greater Chicago and 
other point source dischargers in the area. 

A few largemouth bass were e lectrof ished from the Dres- 
den Pool in 1978 and 1979 (Figure 19-9), adding additional 
evidence to the above hypothesis about recent improved water 
quality conditions in the pool. 

Minnow- seining results from the Dresden Pool in 1978 
and 1979 indicated that emerald shiners, and bluntnose and 
fathead minnows (in addition to the species listed above) 
occur in the shallow main channel border habitats of the 
pool. Emerald shiners were widespread throughout the entire 
river, but Smith (1979:140) noted that while bluntnose minnows 
occur statewide, they prefer hard-bottomed pools in creeks 
and small rivers. This would explain the greater occurrence 
of bluntnose minnows in the upper Illinois River, which 
generally has more hard-bottomed substrates than the middle 
or lower Illinois River. Smith (1979:141) also describes the 
fathead minnow as occurring "most commonly in sluggish 
creeks, ditches, and ponds. In larger streams it occupies 
backwaters and muck -bottomed pools." The presence of fat- 
head minnows in the Dresden Pool may therefore be related 
to the many soft-bottomed areas in the pool. 

Although we have little evidence to document where speci- 
fic spawning areas occur for most fish species in the Illi- 
nois River, the principal species sampled from the Dresden 
Pool, goldfish and carp, are scatter spawncrs and probably 
use the main channel border habitats of the pool to some 
extent for spawning. The few sunfish species that occur in 
the pool probably spawn in suitable habitats in the tribu- 
tary streams of the pool. 

Many of the fish sampled from the Dresden Pool have 
deformities or other pathological conditions. "Poneye" , 
eroded and deformed fins, "knothead" , and bloody sores are 
common. The incidence of these conditions seems to generally 
increase in the upstream direction in the Illinois River as 
a whole, and therefore may be related to chemicals that 
originate from municipal or industrial sources or pathological 
organisms in the water column or sediments. 



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19-51 




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Illinois U'atenvay Fish 19-60 



Marseilles Pool . The Marseilles Pool is approximately 

25 miles long. With the exception of the tail water habitat 
below the Dresden Dam and three small side channel habitats 
(Table G-2), this pool is simply a long relatively straight 
channel consisting of main channel and main channel border 
habitats . 

Small stands of emergent aquatic vegetation (primarily 
sedges and rushes) were observed in this pool in 1978 in 
some of its shallow main channel border habitats. However, 
these stands were not abundant enough to substantially 
affect the fish populations in the pool. 

The substrates of the pool include bedrock, gravel, 
sand, dead shells and hard-packed clay. In contrast to the 
Dresden Pool, little sediment oxygen demand is exerted by 
these substrates (Butts, 1974:29) which apparently are kept 
relatively clean by the faster velocity of the water moving 
through the narrow channel. 

The main tributaries of the Illinois River which flow 
into the Marseilles Pool are the Mazon and Aux Sable Rivers 
(at Illinois River miles 265.6 and 268.3, respectively). 

As in the Dresden Pool, carp, goldfish, and gizzard 
shad dominated the 1959-1975 electrof ishing catch from 
three side channel habitats in the ^larseilles Pool. These 
side channels vere characterized by deep firm bottoms, 
noticeable flow, and underwater brush piles. A number of 
additional species were caught in the Marseilles Pool, 
however, including several members of the sunfish-bass family 
(Family Centrarchidae) , black bullheads, buffalo, goldeye, 
freshwater drum, and As'hite bass (Sparks, 1975:376). This 
increase in kinds of fishes were probably associated with 
better water quality and substrate conditions in the Mar- 
seilles Pool than in the Dresden Pool rather than an increase 
in preferred habitat for these species. 

An exception to this, however, was the black bullhead. 
Numerous black bullheads have been taken from the Ballard 
Island side channel throughout recent times (Figure 19-10). 
These catches suggest that this station contains preferred 
habitat for this species but the key habitat parameters 
within this side channel that are preferred by black bull- 
heads are unknown. Black bullheads are much less abundant 
at the other two side channel stations in the pool. Since 
m.ost catfish are bottom feeders, a possible explanation 
for the large catches of black bullheads in the Ballard 
Island side channel may be a localized increase in bottom 



Illinois Waterway Fish 



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Illinois Waterway Fish 19-62 



fauna density in the side channel as compared to nearby main 
channel and main channel border areas. 

As mentioned earlier in the Dresden Pool discussion, 
recent increases in largemouth bass and black bullhead 
numbers in the Marseilles Pool, together with decreasing 
numbers of goldfish indicated improved water qualtiy condi- 
tions in the 1970 's as compared to the 1960 's , 

Minnow seine results from the ^tarseilles Pool in 1978 
and 1979 were obtained solely from main channel border 
habitats that were characterized by sand, gravel, or bed- 
rock substrates. Along with the ubiquitous gizzard shad and 
emerald shiner, spottail shiners, bluntnose minnows, and sand 
shiners made up substantial portions of the catch (Table 19-4, 19-! 
Spottail shiners are common big-river minnows (Smith, 1979: 
113) and the preference of bluntnose shiners for hard-bottomed 
habitats has been described earlier. The occurrence of sand 
shiners in the Marseilles Pool was probably also related 
to their preference for "large, fast-flowing creeks with 
bottoms of mixed gravel and sand . . ." (Smith, 1979:120). 

The scarcity of carp in the minnow seine catch from the 
Marseilles Pool was undoubtedly related to the substrate 
composition of the habitats sampled. Carp certainly do 
exist in the Marseilles Pool, however, as both the electro- 
fishing (Figure 19-11) and hoopnetting results (Tables 
19-6 and G- 29) indicate. Other bottom feeders such as 
carpsuckers (genus Carpiodes) and catfish (Family Ictaluridae) 
made up most of the remaining hoopnetting catch in the 
Marseilles Pool. The hoopnetting stations were established 
in main channel border and side channel habitats. Since 
rock, gravel, and sand substrates dominate the Marseilles 
Pool, it seems difficult to imagine that these assumed bottom- 
feeder populations can be supported solely by bottom fauna. 
Smith (1979) reports that carpsuckers feed on bottom ooze, 
including diatoms, green algae, blue-green algae, and 
desmids, as well as small invertebrates, and catfish scavenge 
and feed on fish, as well as invertebrates. 

Starved Rock Pool . The Starved Rock Pool is the 
lower-most pool of the upper Illinois River. It is approxi- 
mately 15.4 miles long and like the two pools above it, '< 
contains primarily main channel and main channel border 
habitats (Tables 15-1 and G-2), However, this pool contains 
a substantial amount of side channel habitat and, in addition, 
a rather unique type of habitat that does not easily fall 
into the habitat categories already described. The Starved 
Rock Lock and Dam produces a widening of the Waterway ; 

directly above it for a distance of approximately 4 miles. ! 



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Illinois WaterwaM Fish 19-64 



This widening is not a true mainstem lake becuase within it 
the main channel and a side channel run along the opposite 
sides of a submerged island. 

Scattered stands of emergent aquatic plants exist in 
the shallow, main channel border and side channel habitats 
of the pool. In addition, the side channel that exists 
just above the lock and dam supports minimal submerged aquatic 
plant growth. 

Butts (1974:13) noted that variable substrate types 
were found in the pool. The narrow channels above the lake 
formed by the dam contained relativ^ely clean sand and gravel. 
Localized areas of septic sandy muck, oilv organic muck and 
sludge worms were also found. The lake bottom above the 
dam consisted mainly of muddy sand in the shallows and 
clean sand and gravel in the main navigation channel, but 
again a pocket of oily, black fibrous muck was found in 
this area in the center of the small boat channel at river 
mile 251.7, seven-tenths of a mile upstream from the dam. 

The major tributary to the Illinois River in this pool 
is the Fox River (Illinois River mile 239.7). Although 
dissolved oxygen levels in the Fox River were generally 
close to saturation in 1971 and 1972, the entry of the 
Fox into the Illinois caused only a fraction of a milli- 
gram per liter increase in dissolved oxygen (Butts et al. 
1975). During low flows, an oxygen sag develops in the 
Marseilles Pool and continues into Starved Rock Pool, so 
that Starved Rock Pool has lower oxygen levels during low- 
flows than Marseilles Pool or the upper end of Peoria Pool 
(Butts et al . 1975). Reaeration of the river water does 
not take place at Marseilles dam during low flows, because 
the entire flow of the river is diverted through a power 
plant (Butts et al. 1975). 

The areas sampled by electrof ishing in the Starved 
Rock Pool included side channel and main channel border 
habitats. Carp, goldfish, and carp x goldfish hybrids were 
more abundant in the electrof ishing catch from the Starved 
Rock Pool than in the pools directly above and below it. 
All three of these species can tolerate low oxygen levels 
and their increased abundance in the pool mav be related 
to the higher concentrations of oxygen- demanding sediments 
or the increased populations of sludge worms that occur 
here as compared with the Marseilles Pool. Carp x goldfish 
hybrids occurred more abundantly in the Starved Rock Pool 
than in any other pool of the river, indicating that the 
spawning areas for these species overlap considerably in this 
reach. 



Illinois Waterway Fish 19-65 



White bass begin appearing in substantial numbers in 
the Starved Rock Pool (Figure 19-12). These fish make 
annual spring spawning runs in an upstream direction and 
spawn over hard-bottomed substrates where a current is 
present. It is likely that the Mississippi River serves 
as a source of white bass in the Illinois River but recent 
catches indicate that their indigenous populations in the 
entire river are being sustained at a higher level than 
previously. The increased catches of white bass in the 
Starved Rock Pool in 1978 and 1979 (Figure 19-12) are 
probably related to recent high flows and improved water 
quality . 

Tables G-16 and G-22 show that emerald shiners 
were more abundant in the Starved Rock Pool minnow-seine 
collections than bluntnose minnows, sand shiners and 
spottail shiners, but there were few other differences 
between the small-fish populations of the Starved Rock 
Pool (which were collected from a main channel border and a 
side channel habitat with sand and gravel substrates) and 
those of the Marseilles Pool (Tables 19-4, G-17, and G-23). 
Striped shiners, however, did appear in the 1979 Starved 
Rock Pool minnow-seine collection. This species prefers 
hard-bottomed substrates and moderate currents (Smith, 1979: 
102). The hoopnetting catch from the Starved Rock Pool 
was very similar to that of the Marseilles Pool, the only 
major difference being a slight increase in the abundance 
of channel catfish, a desireable commercial species (Tables 
19-6, G-28 , and G-29 ) . 

As in the Dresden Pool, there were high incidences of 
deformities, eroded fins, stumped barbels and sores on fish 
taken from the Starved Rock Pool, In addition, these 
conditions were commonly seen more on bottom- feeding 
fish than others. Such' condi tions , therefore, may be related 
to factors associated with the substrates in this reach 
more than general water quality conditions. 

Middle Illinois River 

The middle Illinois River contains the Peoria and LaGrange 
Pools. From the "great bend" in the Peoria Pool at Hennepin 
to the Mississippi^River, the Illinois River occupies a 
geologically older valley than it docs upstream of this reach. 
This area is characterized by a broad flocdplain and exten- 
sive bottomland lake habitats (Table 15-1). Although this 
reach has a lo\s'cr gradient than the upper river it is diffi- 
cult to make generalizations about water velocities in the 
pool, especially when referring to different habitat types. 
Both pools in this reach are maintained by relatively low dams 
which are lowered during high flows to allow the passage of 
commercial barges without using the locks. This reach of 



Illinois Waterway Pish 



19-66 



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Illinois Waterway Fish 19-67 



the river has historically been the most productive, in 
terms of fish populations, of the three river reaches, 
largely because of its extensive bottomland lake habitats. 
Recently, however, sedimentation has resulted in a sub- 
stantial loss of these habitats (Bellrose et al. 1979). 

Peoria Pool . The Peoria Pool is approximately 73 
miles long and, as such, is greater in length than all of 
the upper river pools combined. Between the Starved Rock 
Lock and Dam to the Great Bend at Hennepin , the pool 
shifts from a geologically young to an old valley. As a 
result, the upper part of Peoria Pool contains habitats that 
are characteristic of each (Figure 19-13, 19-14). 

Butts (1974:13) described the substrates in the narrov; 
upper reaches of Peoria Pool as consisting of muddy sand, 
with localized areas of thick, oily muck (a situation similar 
to the one observed in the Starved Rock Pool) . Below Lacon 
(18 miles below the "great bend"), however, thick oily muck 
became predominant. Near-shore substrates of sand and gravel 
are often kept free of silt by wave action (Figure 19-14). 
Below the "great bend", the turbidity of the Illinois River 
also increases substantially (Figure 2-4). This increase in 
turbidity is related to the fact that most of the bottomland 
lakes of the Peoria Pool have relatively permanent connec- 
tions to the river at all flow rates and that the fine 
sediments that characterize these lakes are easily stirred 
up by wind and boat -generated waves. 

Little aquatic vegetation occurs in most of the bottom- 
land lakes in the Peoria Pool (Figure 19-15). The off-shore 
substrates of the lakes are not firm enough to support vas- 
cular plants during windy or otherwise turbulent periods. 
In addition, the average depths of most of the bottomland 
lakes of Peoria Pool described in the terrestrial section 
of this report (Chapter 4) were less than 2 ft. 

Peoria Pool contains the only natural mainstcm lake, 
Peoria Lake, on the Illinois River. Peoria Lake encompasses 
approximately the lower third of the Peoria Pool. This lake 
is also filling rapidly with sediment (although as a slower 
rate than most of the bottomland lakes). The main channel 
remains narrow as it winds its way through Peoria Lake until 
it reaches the city of Peoria. The non-channel area of the 
lake is primarily composed of soft silt substrates except 
for areas where springs and creeks enter it or where continu- 
ous wave action exposes sand substrates. This also occurs 
in some of the bottomland lakes of the Peoria Pool. As in 
the bottomland lakes of this pool, Peoria Lake contains 
almost no aquatic vascular plants. 



Illinois Kateriv-av Fish 



19-68 







,^ 







- -^ J 



Figure 19-13. A main channel border minnow- seine station 

in the Peoria Pool at River Mile 229.4. Although 
this station was in the Peoria Pool, it was also 
above the "great bend" in the Illinois Piver 
and shows the narrow channel and the bedrock and 
boulder substrates that exist along much of the 
upper Illinois River. 



Illinois U'atenv-av Fish 



19-69 




r::!- 



^;'-t.--. , 



.V-i-. 




£:w" 



Figure 19-14.A main channel border minnow-seine station in 
the Peoria Pool just below the "great bend" at 
River Mile 207. Note the gentlv sloping sand and 
gravel substrates . 



Illinois Waterway Fish 



19-70 










%?^ 



*atT'-- . . . . try, :!, ^.^.■■ , .. ,,_ 




Figure 19-15. A bottomland lake (Sawmill Lake) minnow-seine 
station in Peoria Pool, River ^'ile 197. No 
current existed at this station but the sub- 
strate was similar to that of main channel 
border habitats in this reach. Note the lack 
of aquatic vegetation and the fishing sticks 
pushed into the beach in the background. 



Illinois Waterway Fish 19-71 



The only major tributaries to the Peoria Pool are the 
Vermilion (Illinois River mile 226.4) and Little Vermilion 
rivers (Illinois River mile 225.6). Numerous small creeks 
flow into the pool but these have considerably lower average 
(or sometimes intermittent) discharges. 

Most of the electrof ishing stations sampled in the 
Peoria Pool were in side channels and main channel border 
habitats (Table G-2) because of the difficulty in maneuver- 
ing the electrof ishing boat in shallow bottomland lakes. 
These habitats were typically deep channels with noticeable 
current, hard clay, or mud/sand bottoms, with cover provided 
by fallen trees. The catch from these habitats were usually 
substantial both in quantity and diversity although bottom- 
feeding fish clearly dominate the catch. The most common 
fishes taken were carp, gizzard shad, buffalo (genus Ictiobus) 
carpsuckers (genus Carpiodes) , green sunfish, bluegill, 
largemouth bass, white and black crappie , and freshwater 
drum . 

The extensive bottomland lakes undoubtedly provide 
desireable habitat and some invertebrate fauna for may of 
the species noted above. In areas in these lakes where the 
substrates are firm, increased spawning habitat is also 
provided . 

Fish produced in areas lateral to the river are 
recruited to side channels and suitable main channel border 
habitat where they are sampled by electrofishing , but minnow 
seining results provided a direct indication of how bottomland 
lakes can affect fish productivity. In 1978, bottomland lake 
stations were sampled by minnow- seining in Peoria and LaGrange 
Pools and contributed heavily to the high total fish per 
haul values (100 and 90, respectively) observed in these 
pools (Tables 19-4, IS- 1 4 , and n- 1 S) . A high total fish 
per haul value was also obtained in the Alton Pool in 1978, 
but this was primarily the result of large numbers of a 
single species, gizzard shad. In 1979, the bottomland lake 
stations were not included in the minnow-seine program 
(Table G-2), for reasons detailed earlier, and the total 
fish per haul values for the Peoria and La Grange Pools (Table? 
19-5, G-20, G-21) decreased to levels that were difficult 
to distinguish from those of the other river pools (Table 
19-5), which have far fewer or no bottomland lakes. There- 
fore, in spite of the fact that most of the bottomland lakes 
of the middle Illinois River are being degraded by sedimen- 
tation, they are apparently still playing a major role in 
the production of the river's small-fish populations. 
However, the overall relationship between Illinois River 
bottomland lakes and fish production is undoubtedly deter- 
mined by several factors, including (but not limited to) 



Illinois Waterway Fish 19-72 



1) the degree (areal and temporal) of connection between 
the river and the lake; 2) the inflow of water into the lake 
from sources other than the river; 3) the depth, composition 
and hardness of the lake's bottom; and 4) the amount and 
kinds of food and habitat available in the lake. While 
the presence of these factors makes it impossible at this 
time to quantify the relationship between bottomland surface 
area and fish populations in the river, our minnow seine 
results clearly indicate that a positive relationship does 
still exist between them. 

The minnow-seine catch from main channel border habi- 
tats (which were typically gently sloped with variable com- 
positions of mud, sand and gravel) in the Peoria Pool 
below the "great bend" was dominated by gizzard shad, emer- 
ald shiners and spottail shiners. Most of the sunfish species 
collected by minnow seining from the Peoria Pool were 
collected in bottomland lake habitats or in Peoria Lake. 
The scarcity of fathead minnows in our minnow-seine collec- 
tions from the Peoria Pool may be related to our emphasis 
on main channel border stations where some current was usu- 
ally present, to the inability of fathead minnows to compete 
with young gizzard and emerald shiners in this reach, or 
to a lack of overhanging substrates (ie. aquatic plants) for 
them to lay eggs under. 

Largemouth bass were much more abundant in the electro- 
fishing catch from the Peoria Pool in the 1970's than in the 
1960 's (Figure 19-9). This increase probably was related 
to the higher river flows and subsequent increases in 
habitat availability that occurred in the 1970's. 

While changes in fish populations of the middle Illi- 
nois River over the last twenty years can be assessed using 
electrof ishing results, comparisons with earlier periods 
requires the use of hoopnetting data. Although the follow- 
ing analysis was based on data generated primarily from 
areas along the middle and lower river (Thompson, unpub- 
lished; Atwood, unpublished; Sparks et al . 1979), it per- 
tains most to the middle reach of the river and is there- 
fore included in this section. Figure 19-16 shows the 
percent of total catch of four surveys contributed by six 
fish species and two other fish groups, catfishes and carp- 
suckers, during four independent hoopnetting surveys of 
the Illinois River. The most important catch changes 
illustrated in this figure are the decreasing contributions 
of the sunfish (crappies and bluegills) through time and 
the increasing contributions of gizzard shad and carpsuckers. 



Illinois Waterway Fish 



19-73 



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Illinois Waterway Fish 19-74 



The common use of wings and leads (nets used to direct 
fish into the hoops) before the 1978-1979 survey, but not 
during it, may have resulted in the 1978-1979 percentages 
for crappies and bluegill in Figure 19-16, being lower 
than they might have been if wings and leads had been rou- 
tinely used in 1978-79. This sampling difference, however, 
could not have explained the indicated decreases in the sun- 
fish that took place before the 1978-79 survey, the dramatic 
increases in carpsuckers that have occurred since the 1957- 
67 period, or the increases in gizzard shad that have occurred 
since 1942. These catch changes are probably directly 
related to major habitat, food supply, and water quality 
changes that have affected the rivers bottomland lakes 
during this period. 

Crappies and bluegills are nest builders and sight 
feeders. Their populations in the Illinois River have 
therefore almost certainly been limited by increased sedi- 
mentation which has reduced the amount of spawning areas 
available, and turbidity levels which make it more difficult 
to locate and capture prey. The present lack of aquatic 
vegetation in the river has also greatly reduced the "weed 
fauna" available for them to feed on. the carosuckers 
on the other hand are much more adapted to these present 
conditions. They do not require hard-bottomed substrates for 
their "broadcast" spawning activities (Smith 1979:154) and 
are equipped to feed off bottom ooze (including diatoms, 
green algae, zooplankton (Smith 1979:154). 

Carp have not shown the dramatic increases that carp- 
suckers have during the period covered by these surveys, 
apparently because they were already populating the river 
at or near maximum levels during the earlier surveys. Note 
that 32 species of fish were taken by hoopnetting in Peoria 
Pool in the 1978-79 hoopnetting surveys (Table G-27 ) , but 
that only eight species or families which comprised a large 
percentage of the catch or whose numbers changed dramatically 
during the four hoopnetting surveys are shown in Figure 19-16. 

LaGrange Pool . The LaGrange Pool is approximately 
77 miles long and similar to the Peoria Pool in several 
ways. It has a low gradient, extensive bottomland lake 
habitats, almost no aquatic vascular plants and is heavily 
degraded by sedimentation. The LaGrange Pool is different 
from the Peoria Pool in that most of its bottomland lakes 
are "perched" above the river bed and require various tvpes 
of control structures to retain water during low flows, it 
contains no mainstem lake, and it does have several large 
tributaries flowing into it. 



Illinois Waterway Fish 



19-75 



The substrates of the pool range from course sand in 
its main channel habitats, to hard-packed clay in its deep 
side channels, to flocculent "false bottoms" -- half water 
and half silt -- in its bottomland lakes and sloughs. 
Occasionally, the main channel runs very near the banks of 
the river, creating sharp dropoffs in main channel border 
areas. The pool has one particularly large side channel, 
Bath Chute (Illinois River miles 106.8-113.4), and a verv 
complex slough and bottomland lake system where the Sanga- 
mon River flows into the Illinois River (Illinois River 
miles 88.8-98.0). The other major tributaries of the pool 
are the Spoon (river mile 120.5), Mackinaw (river mile 147. 
and LaMoine Rivers (river mile 83.7). 



') 



The fish populations of the LaGrange pool are quite 
similar to those of the Peoria Pool, being dominated by carp 
and other bottom feeders. There is one general exception 
to this rule, however. Fish species that are probably 
recruited into the Illinois River from the Mississippi River 
are more abundant in the LaGrange Pool. These include short- 
nose gar, bowfin, goldeye, mooneye, channel catfish, flat- 
head catfish, and white bass. Figure 19-17 shows this 
relationship for channel catfish. 

Minnow-seine (Tables G-14 , G-15 , G-2n, and G-21) and 
hoopnetting catches (Tables G-26 and G-27) from the LaGrange 
Pool were generally similar to those obtained in the Peoria 
Pool. One notable exception was the remarkable diversity of 
sunfish seined from Matanza Lake in the LaGrange Pool in 
1978. This collection was made at a point in this bottom- 
land lake where an underground spring flowed into it, and 
included a remarkable number of brook silversides. 

The Lower Illinois River 

The lower Illinois River consists of one pool, the 
Alton Pool, which is created by the Alton Lock and Dam on 
the Mississippi River approximately 15 miles below the con- 
fluence of both rivers at Grafton, Illinois. Since this 
report was designed to address the Illinois Watencay, both 
the Illinois River reach of this pool and the ^!ississippi 
River reach of the pool between Grafton, Illinois and the 
Alton Lock and Dam will be discussed here. 

The Illinois River reach of the Alton Pool from 
Grafton, Illinois to the LaGrange Lock and Dam, is approxi- 
mately 80 miles long. The primary difference between this 
reach of the Alton Pool and the middle Illinois 
River is that it has been substantially constricted into 
a relatively narrow channel by agricultural levees. Kith 
the exception of Lake ^leredosia, the upper 70 mile reach of 



Illinois Waterway Fish 



19-76 



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Illinois Waterway Fish 19-77 



the pool is essentially void of bottomland lalces. This 
reach therefore contains primarily main channel and main 
channel border habitats, several side channels, and bottc. 
land lakes in its lovv^er 10 miles (Table G- 2) , Substrates 
in this reach range from course sand in the main channel to 
thick silt deposits in some of the low velocity main 
channel border and side channel habitats of the pool. 
Little aquatic vegetation exists in the pool. Only small 
streams and creeks are tributaries to this pool. This reach 
contains several stone wingdams that were built to constrict 
the flow of river into the main channel. The numbers and 
kinds of benthic macroinvertebrates found in this reach are 
considerably greater than in upstream reaches. [See 
Chapter 18, Macroinvertebrates). 



The Mississippi River reach of the pool between its 
confluence with the Illinois River and the Alton Lock and 
Dam is much broader and has a considerably larger flow than 
the Illinois River. This reach contains extensive main 
channel, main channel border, and side channel habitats 
but limited bottomland lake habitats. Much of the east 
bank of this reach has been rip-rapped to protect it 
from wave action and the reach contains numerous wingdams. 

Alton Pool Fish Populations . Elect rofishing stations 
in both the Illinois and Mississippi Reaches of the Alton 
Pool were, as before, usually established in side channels 
having noticeable current and brushy cover. Coldeye, mooneye, 
channel catfish, flathead catfish and white bass in partic- 
ular occurred at their highest levels in the Alton Pool 
electrofishing catch. The catch in this pool however was 
still dominated by carp and gizzard shad. However, carp, 
buffalo (genus Ictiobus) and carpsuckers (genus Carpiodes) 
occurred less in the Alton Pool than in the middle Illinois 
River, probably because of the decreased bottomland lake 
habitats in this pool. 

Minnow-seine collections from soft-bottomed main channel 
border and side channel habitats in the Illinois River reach 
of the Alton Pool (Table G-13 and G-19 ) were also similar 
to those obtained in the middle Illinois River, with notable 
increases in the number of black crappie and drum caught. 
The hoopnetting catch (G-25) also indicated an increase 
in the number of black crappie caught. 

In general, the species taken from the side channel 
and main channel border habitats in the Mississippi River 
reach of the Alton Pool were similar to those taken from 
the Illinois reach. Notable differences were increases in 
the electrofishing catch of channel catfish, and minnow- 



Illinois Watenvay Fish 19-78 



seine collections of silver chub and sauger. Smith (1979: 
82) noted while the silver chub is primarily a fish of large 
rivers and lakes, it occurs commonly in the lower reaches 
of their major tributaries. The appearance of sauger 
in this reach also fits Smith's (1979:257) description of 
its distribution as being rather general in the Mississippi 
River, but sporadic in other large rivers of the state. 

Illinois River Summary 

The commercial harvest of fish from the Illinois River 
is only a fraction of its size at the turn of the century. 
Since the commercial harvest in the neighboring Mississippi 
River has remained relatively stable since the 1950's but 
the Illinois harvest has continued to gradually decrease, 
it appears that the cause of the decrease is biological 
rather than economical in nature (ie. related to smaller 
commercial fish populations rather than fewer numbers of 
fishermen) . 

The most abundant fishes in the Illinois River in 
recent years were: carp and gizzard shad in the electro- 
fishing catch; emerald shiners, gizzard shad and spottail 
shiners in the minnow-seine catch; and, bottomfeeders 
(particularly carpsuckers, carp and catfishes) in the hoop- 
netting catch. Many species were more abundant in a cer- 
tain reach of the river or a particular habitat than others 
however and therefore do not readily support generalizations 
covering the entire river. Many desirable fish species 
such as largemouth bass, crappies and other sunfish were 
more numerous in the LaGrange and Peoria Pools which have 
the most bottomland lake areas of the river. Bottomland 
lake habitats also continue to support relatively greater 
numbers of fish than other habitats, as indicated by the 
1978-79 minnow-seine catch. This is in spite of the fact 
that most of the bottomland lakes of the middle river are 
being severely affected by sedimentation and turbidity. 
However, a comparison of hoopnetting results obtained in 
1978-79 with those of previous surveys indicated major shifts 
in species compostion in the middle river -- with bottom- 
feeding "broadcast" spawners (carpsuckers) replacing sport 
fish (crappies and bluegills) over the last 40 years. 
This replacement probably relates to the problems of 
increasing sedimentation and turbidity in the river and its 
bottomland lakes. 



Illinois Waterway Fish 19-79 



Recent increases in largemouth bass, white bass and 
black bullhead electrof ishing catches, and corresponding 
decreases in goldfish electrof ishing and hoopnetting catches 
in the upper river indicate that improved water quality condi 
tions are benefiting the fish populations of this reach. 
However, we were not able to determine to what extent the 
apparent water quality improvements were due to improved 
waste treatment practices as opposed to dilution condi- 
tions related to recent high river flows. Also, 
while these changes indicated the existence of improved 
water quality conditions in the upper river, the patho- 
logical conditions of many bottom feeding fish, especially 
in the Starved Rock Pool, indicated that a factor related 
to the river bottom in this reach was impairing fish health. 



THE IMPACTS OF INCREASED DIVERSION 
ON ILLINOIS WATERWAY FISH POPULATIONS 

Based on the expected physical and water quality 
changes that will accompany increased diversion (Chapter 2), 
it seems appropriate to discuss the impacts of these changes 
on the fish populations of the waterway from two points 
of view. The first of these concerns the impacts increased 
diversion will have on water quality; the second, its 
impacts on habitat quantity and quality. 

Impacts Related to Water Qualtiy Changes 

In terms of water quality, we expect the increased 
diversion will have its greatest impact nearest the intake 
points on the waterway where the actual diversion will take 
place, and in addition that the beneficial effects of 
increased diversion on water quality will decrease with 
increasing distance downstream from these points. The pri- 
mary water quality factors affecting fish populations that 
will be influenced by increased diversion are dissolved 
oxygen concentrations, toxicant concentrations (such as 
ammonia, heavy metals, etc.), and suspended solids concen- 
trations. Diversion-related changes in temperature, mineral 
content, and nutrient levels should not dramatically affect 
the fish populations of the waterway (Illinois State Water 
Survey, 1979). Diversion- related increases in suspended 
solids in the upper ateru'av will probably be temporary in 
nature and particularly associated with sudden increases 
in diversion. Dissolved oxygen and toxicant concentration 
changes related to increased diversion will probably be 
most extreme in the reaches of the waterway between the 



Illinois Waterway Fish 19-80 



treatment outfalls of the Metropolitan Sanitary District 
of Greater Chicago and the confluence of the Des Plaines 
and the Kankakee Rivers, Impacts related to suspended 
solid levels will primarily be through interactions with 
dissolved oxygen and toxicants in the Chicago-area reaches 
of the waterway but also through sedimentation, turbidity, 
and habitat quality changes in the middle and lower Illi- 
nois River. 

The potential impacts of dissolved oxygen, toxicant 
and suspended solids changes on the waterway's fish popu- 
lations are discussed below. However it should be noted 
that these factors interact to sometimes offset and some- 
times enhance each other's effects on fish populations. 
Such potential interactions and the difficulties they 
present in predicting the impacts of increased diversion 
are also discussed. 



Dissolved Oxygen 

Dissolved oxygen (D.O.) concentrations in the waterway 
are expected to increase with increased diversion (Chapter 
2). The beneficial impacts these increases will have on 
the Waterway's fish populations will be dependent on the 
magnitude and duration of the increases. In addition, 
these impacts will primarily be restricted to the upper 
Illinois Waterway, in particular the Chicago-area reaches 
between the outfalls of the Metropolitan Sanitary District 
of Greater Chicago and Kankakee River, 

In the upper reaches of the waterway, low D.O. concen- 
trations not only affect fish populations by limiting their 
respiration, but also by enhancing the toxic effects of 
many substances (Merkens and Downing, 1957; Pickering, 1968) 
Increased diversion, therefore, will benefit fish popula- 
tions in the upper waterway by offsetting both of these 
existing limitations. 

Interacting factors . Two interacting factors may 
influence the effects of increased diversion on D.O. concen- 
trations and subsequently fish populations in the upper 
waterway. The first of these is the increased oxygen demand 
that may be created by resuspended s ludgc- depos i ts if 
diversion flows are increased suddenly. Data from the 1940 
"Flushing Experiment" on the upper waterway indicated that 
at Lockport, 5-day oxygen demand values increased from 
approximately 15 ppra to approximately 55 pDm during a 24- 
hour period when flow rates were increased from 2,708 
Sec. ft, to 10,770 Sec. ft. (U.S. Corps of Engineers, 1979). 



Illinois Waterway Fish 19-81' 



This increased oxygen demand was associated with a simul- 
taneous increase in suspended solids from 18 to 300-400 
ppm . This oxygen demand will probably not exert its maxi- 
mum impact on D.O. concentrations in the areas of the upper 
waterivay where the sludge beds now exist, but within several 
days of travel downstream from these areas. In short, 
the area of the upper waterway presently affected by sub- 
stantial B.O.D.'s will be extended downstream. The actual 
detrimental effects of this extension on fish populations 
in the upper waterway will be offset by increases in D.O. 
concentrations resulting from the use of high quality 
Lake Michigan water for diversion. Much of the increased 
B.O.D. due to resuspended sludge deposits however is 
expected to be temporary in nature, reaching maximum values 
after sudden increases in diversion flow and decreasing 
gradually thereafter. 

The second interacting factor affecting D.O. concen- 
trations in the upper and middle waterway is the presence 
of ammonia in the waterway. The bacterial decomposition of 
ammonia in the waterway creates an oxygen demand, and reduces 
the amount of oxygen available for fish respiration. Butts 
et al. (1975:30) noted that "the location in the waten\'ay 
at which ammonia oxidation becomes significant depends on 
the hydrologic and hydraulic conditions of the wateru^ay" . 
Once again, increased diversion will probably shift this 
location farther downstream than it would be otherwise. 

We do not know to what extent these interacting factors 
have been taken into account in the models that have been 
used to simulate D.O. concentrations in the upper waterway 
under different diversion rates (Chapter 2). It may be, 
however, that because of all these interacting factors 
actual dissolved oxygen concentrations in the upper water- 
way during diversion will have to be monitored rather than 
modeled. Until then, the impacts of diversion- related D.O. 
changes in the upper watenN'ay on fish populations will be 
subject to a certain degree of speculation. 



Toxicant Concentrations 

In order to estimate quantitatively the dilution effects 
of increased diversion on toxicant concentrations in the 
waterway, we have used a toxicity index system which is 
based on the bluegill 96-hr LC50 (lethal concentration to 
50-0 of the bluegills exposed over 96 hours) values for 



V 



Illinois Waterway Fish 19-82 



several known toxic constituents of the waterway. As with 
D.O. concentrations, the effects of increased diversion 
effects on dilution of toxicants is generally expected to 
be greatest in the Chicago-area reaches of the waterway. 
In fact, Lubinski (1975) noted that toxicity values gener- 
ated for the waterway using the toxicity index system, rarel 
exceeded lethal levels below the Dresden Pool. Therefore, 
except during occasional spills, water column toxicant 
concentrations may not substantially affect fish populations 
in the Illinois River reach of the watenvay. It should 
be noted though that the toxicity index system described 
here does not address sublethal or bi oaccumulat ive effects. 

The water diverted from Lake >'ichigan has very low 
concentrations of toxic substances. The average Bluegill 
Toxicity Index value, the measure of water quality utilized 
in this report, is 0.029 BGTU for 30 lake sites (Brigham 
et al. 1978). Thus, the water available for diversion is 
essentially free of toxicants and the reduction in toxicity 
resulting from increased diversion was estimated by straight 
dilution of existing mean toxicant concentrations. 

The waters of the channels receive a very high input 
of toxic substances. The mean loadings of these toxic sub- 
stances are considered a constant for this analysis. Thus, 
an inverse relationship of increasing flow rates to decreasing 
toxicity values can be calculated. Figures 19-18 through 
19-21 depict this relationship for the initial inland 
stations on each of the intake waten\'ays which have toxicity 
values not greatly improved by the present diversion. In 
addition, these sites may possibly be improv^ed by increased 
diversion. The figures indicate the minimum diversion rates 
at which the toxicity of the stations would be reduced to 
0.200 BGTU {(the point at which water quality becomes favor- 
able to a diverse fishery (Lubinski and Sparks, 1980)} 
and the maximum controllable diversion rate for each of the 
intake structures. The diversion flow rates would have to be 
maintained within these ranges to reduce the toxicity index to 
a level likely to permit survival of a diverse fish popu- 
lation . 

Water is diverted through the North Shore Channel at 
an average of 141 cfs (Northeastern Illinois Planning Com- 
mission, 1978). This value includes controllable diversion 
plus uncontrollable diversion due to lockage, leakage, and 
navigation. The 1976 Illinois Environmental Protection 
Agency mean concentrations of toxic substances for the 
first two inland sites likely to be improved bv increased 
diversion were averaged to compute a toxicity value (0.675 



Illinois Waterway Fish 19-83 



BGTU) for this waterway. To decrease this average toxicity 
value to 0.200 BGTU, the diversion rate would have to he 
maintained above 470 cfs to improve the Waterway through 
the length of the Channel (Figure 19-18). 

The toxicity of the Chicago River is increased to 0.854 
BGTU before the river joins with its north and south branches 
[Brigham et al., 1978). A minimum flow rate of 1500 cfs 
would be required to dilute this toxicity value to 0.200 
BGTU (Figure 19-19). The present mean flow rate is 352 
cfs (Northeastern Illinois Planning Commission, 1978). 

The average concentration of toxicants from two sites 
on the Calumet River likely to be improved by increased 
diversion was utilized (one site lakeward and one site 
inland from the O'Brien Lock). The present mean flow rate 
is 505 cfs (Northeastern Illinois Planning Commission, 1978). 
To reduce the joint toxicity of 0.219 to 0.200 BGTU, the 
rate would have to be maintained above 550 cfs , a small 
increase (Figure 19-20). This waterway was further evalu- 
ated by calculating the minimum flow rate required to re- 
duce the toxicity value of the first downstream site on 
the Little Calumet River, the recipient of diversion flow 
from the Calumet River. A minimum diversion flow of 2800 
cfs would be required to reduce the mean toxicity value of 
1.120 (Brigham et al . , 1978) to 0.200 BGTU (Figure 19-21). 

The above calculations were based on mean annual toxicant 
concentrations and flow in the waterways. Since the increased 
diversion will occur during typical low-water periods (summer 
and winter) these calculations only approximate the actual 
toxic conditions that will exist in the waterways. During 
periods of natural (noncontrollable) high flows, the diver- 
sion of relatively cleaner Lake Michigan water into the 
Waterway will be reduced and dilution effects will decrease. 
During periods of heavy rainfall and runoff in the Chicago 
area, the stormwater in the combined sewers exceeds the flow 
capacity of the sewage treatment plants, and a mixture of 
stormwater and raw wastewater flushes directly into the water- 
ways. The mixture contains toxic materials, oxvgcn- demanding 
wastes, and suspended solids. The concentration of these 
materials depends on the intensity and duration of rain- 
fall in the Chicago area. The concentration is usually 
highest at the beginning of the rain, when accumulated material 
in drains and on streets is first flushed into the waterways. 
Thereafter, continued rainfall may dilute the wastes. As 
various segments of the Chicago Deep Tunnel and Reservoir 
Plan (a plan to store stormwater underground until it can be 
pumped out and treated in existing sewage treatment plants) 
are completed over the next several years by the >iet ropol i tan 



Illinois Waterway Fish 



19-84 




Figure 1Q-18. Inverse relationship of increasing percentage 
of diversion flov to decreasing toxicity 
values for the North Shore Channel. The 
mininium diversion rate at vhich the toxicity 
is reduced to 0.200 BHTIJ and the maximum 
controllable diversion rate for this intake 
point are indicated. 



Illinois Waterway Fish 



19-85 



35 




Figure 19- 19. Inverse relationship of increasing percentage 
of diversion flow to decreasing toxicity 
values for the Chicago River. The minimum 
diversion rate at which the toxicity is 
reduced to 0.200 BGTU and the maximum con- 
trollable diversion rate for this intake 
point are indicated. 



Illinois Waterway Fish 



n-86 




figure 19-20. Inverse relationship of increasing percentage 

of diversion flow to decreasing toxicity values 
for the Calunet River. The mininum diversion 
rate at which the toxicity is reduced to 0.200 
BHTU and the maxiinum controllable diversion 
rate for this intake point are indicated. 



Illinois Waterway Fish 



19-87 




TXDXICITY LNDEX 
(Bluegdl Toxicity Uniu) 



Figure 19-21. Inverse relationship of increasing percentage 

of diversion flow to decreasing toxicity values 
for the Little Calumet River. The minimuni 
diversion rate at which the toxicity is reduced 
to 0.200 BGTU and the maximum controllable di- 
version rate for this intaVe point are indicated 



Illinois Waterway Fish 19-88 



Sanitary District of Greater Chicago, the input of pollutants 
to the watervs-ays during rainstorms and high flows should 
be reduced. Hence, water quality in the waterways, during 
and following rainstorms in the Chicago area, should improve 
even without the benefit of dilution from Lake Michigan 
diversion . 

The following is a brief summary of the preceding discussion 
concerning our efforts at quantifying the effect of increased 
diversion on the dilution of toxicants in the Chicago-area 
reaches of the waterway. 

If the minimum flow rates detailed above were maintained, 
it would be possible to improve water quality in the upstream 
portion of the upper Illinois Watenvay to a level which 
would permit the survival of a diverse fish population. 
However, it is unlikely these flow rates will be maintained 
due to the seasonal differences in the amount of uncontrol- 
lable diversion waters. Rather, the mean toxicity of the 
channel waters probably will be improved, but not to or 
below the 0.200 level. 

The improvement of the water quality may result in an 
enlargement of the transition zones and maximum penetration 
distance, but this will not necessarily improve the quality 
of the channel fish fauna. Additional non-lake fish species 
would not have access to the upstream portions of the upper 
Illinois V.'aterway due to the toxicity of the intervening 
waterways. If additional species were stocked in the area, 
they probably could not survive the high toxicity during 
those periods when the rate of diversion was reduced. As 
is now the case, lake species entering the area also could 
not survive reduced diversion flow. Thus, while some im- 
provement in water quality is anticipated, it is unlikely 
that increased diversion from Lake Michigan would produce 
a change in the dominant fish species of the upper Illinois 
Waterway . 



Interacting factors . One principal interacting factor 
could alter the assumptions that were used above in quanti- 
fying the dilution effects of increased diversion on upper 
waterway toxicant concentrations. This factor is the role 
that the existing sludge deposits of the upper waterway could 
play in the adsorption and release of toxicants. ^'any 
toxicants are known to have a greater affinity for sediments 
and suspended solids than water. As a result, sediments 
normally have higher concentration of toxicants than filtered 
river water samples (Mathis and Cummings, 1973). It could 
be hypothesized that increased suspended solids concentrations 
resulting from sudden increases in diversion will increase 
the degree of contact between the water and the particles 
involved. However, the rates of adsorption and release of 



Illinois Waterway Fish 19-89 



toxicants under varying conditions in the Chicago-area 
reaches of the waterway are not known and no conclusions 
could be drawn about the effects of increased diversion 
on either. 



Suspended Solids 

The impacts of increased diversion on suspended solids 
in the upper waterway have been discussed earlier under inter- 
actions with D.O. and toxicant concentrations. But in the 
middle and lower Illinois River suspended solids concentra- 
tions could present major problems to fish populations through 
habitat quantity and quality changes which are discussed 
in the next section. 



Impacts Related to Aquatic Habitat 
Quantity and Quality 

This section includes a discussion of 1) the relationship 
between increases in aquatic habitats that will occur under 
increased diversion rates and the fish populations of the 
Illinois River and 2) corresponding increases or decreases 
in aquatic habitat quality. The increases in river veloci- 
ties noted in Chapter 2 are not expected to directly affect 
the waterways fish populations except for occasionally con- 
tributing to the transient movement of Lake Michigan species 
into the upper waterway. Our discussion of the relationship 
between aquatic habitat quantity and fish populations is 
limited to an analysis of statistical correlations between 
water levels and recent electrofishing catches in the LaHrange 
Pool since they were typical of those observed in the Peoria 
Pool and because the effects of increased diversion on fish 
populations in the upper waterway are expected to be through 
changes in water quality rather than quantity. 

Aquatic Habitat Quantity and Fish Populations 

Fish production in the Illinois River has long been con- 
sidered dependent on the natural annual cycles of high and 
low flows that typify temperate streams. In 1894, the Havana 
Field Station of what was then called the State Laboratory of 
Natural History had as its special assignment by S.A. Forbes, 
the study of the effects of periodical overflows and recessions 
of Illinois River water on the plants and animals of the 
system (Bennett, 1958:165). In general, it is commonly 
believed that high river flows in the spring are good for 
fish populations, stimulating increased production by pro- 



Illinois Waterway Fish 19-90 



viding increased spawning areas and habitat for juvenile 
fish. Alvord and Burdick (1915) (in Forbes and Richardson, 
1919:154), were the first to attempt to quantify the rela- 
tionship between high river flows and fish production 
(Figure 19-22). Forbes and Richardson interpreted these 
results as indicating that there was a "good correlati.on 
of production with the area of overflow" (Forbes and 
Richardson, 1919:154). Since a relationship such as this 
could conceivably be a major beneficial effect of increased 
diversion, we attempted to quantify the recent relationship 
between flow (using river water levels as a measure) and 
fish populations in the river. 

Statistical correlations were performed using electro- 
fishing catch data from LaGrange Pool covering the period 
1959-1975 for largemouth bass, green sunfish, bluegill, 
white bass, carp and channel catfish, and annual, seasonal, 
and spawning-period water levels at Havana, Illinois. Daily 
water levels during the following periods were used to calcu- 
late seasonal averages: winter, December 4-March 4; spring, 
March 5-June 4; summer June 5-September 3; fall, September 4- 
December 3. Average spawning period water levels were based 
on daily measurements during the following periods: large- 
mouth bass, April 9-June 11; green sunfish. May 7-August 20: 
bluegill May 21-September 3; white bass, March 5-April 29; 
carp, March 19-July 2; channel catfish. May 21-July 23. 
The Spearman rank correlation coefficient statistic, r^ , was 
used as a measure of correlation between these water level 
periods and numbers of fish caught per 30 minutes of electro- 
fishing because the statistic is non-parametric and appli- 
cable to data sets were either variable, in this case water 
levels, is not normally distributed (Zar, 1974:49 8-499, 
Table D24) . Table 19-7 contains the Spearman rank correlation 
statistic values for the various periods and species (Number 
of years=N=14) . Significant correlations at the 0.20 and 
0.10 levels of probability are also indicated. 



As can be seen in Table 19-7, few significant correla- 
tions between electrof i shing catch and water levels were 
observed. A certain percentage of significant correlations 
at these levels could be expected in any large set of values. 
For the few correlations that did prove statistically signifi- 
cant, no pattern seemed to stand out, but it was noted that 
while not being statistically significant at the 0.20 level, 
all of the correlations between the carp catch and different 
water level periods were negative. This implies that there 
could be some direct relationship between high carp popula- 
tions in the river and low water levels. Electrof ishing 
was always conducted during late summer when the river was 
at pool stage so that arguments that these results reflect 
the effects of water levels on sampling efficiency rather 



Illinois Waterway Fish 



19-91 



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Illinois Waterway Fish 19-92 



Table 19-7. Spearman rank correlation coefficients (rg) for 
electrof ishing catch (number caught/30 minutes) 
vs average water levels, LaGrange Pool 1959- 
1975 (N=14) . 



Average 
Water Levels 


Large- 
Mouth 
Bass 


Green 
Sunf ish 


Bluegill 


White 
Bass 


Carp 


Channel 
Catfish 


Winter 


0.21 


0.42* 


0.13 


-0.20 


-0.05 


0.10 


Spring 


0.22 


-0.01 


0.12 


0.40* 


-0.59 


-0.28 


Summer 


0.05 


0.54** 


0.23 


0.14 


-0.24 


-0.01 


Fall 


-0.37 


0.013 


-0.54** 


0.13 


-0.38 


-0.48* 


Annual 


-0.05 


0.33 


0.03 


0.41* 


-0.50 


-0.17 


Spring- 
Summer 


0.14 


0.25 


0.14 


0.26 


-0.54 


-0.12 


Spawning 
Period 


0.13 


0.38 


0.22 


0.24 


-0.49 


0.09 



* Significant at a 0.20 level of probability 
** Significant at a 0.10 level of probability 



Illinois Watervk'ay Fish 



19-9 3 



than actual populations should be unfounded. We are unable 
to confidently explain the consistent negative correlations 
between carp catches and water levels, although if high water 
levels benefit game fish in the river, they may prey upon 
young carp. If high water levels benefit catfishes, drum, 
and carpsuckers, they may compete with carp for food. 

We attempted to calculate similar correlation statis- 
tics for the Peoria Pool, and also by using 1-vear lag periods 
between water levels and the electrof ishing catch to take 
into account the fact that our electrof ishing catch generally 
excludes small, young-of- the-year fish. However, these 
additional attempts at quantifying the relationship between 
water levels and fish populations in the river as measured 
by the electrof ishing catch yielded results similar to those 
in Table 19-7 and did not generate any additional useful 
information . 



Rather than suggest that no relationsh 
between water levels and fish populations i 
results probably indicate that other variab 
affecting the river's fish populations and 
fering with our ability to quantify this re 
instance, changes in the river's food resou 
quality over the period of time covered by 
lations may well have resulted in changes i 
fish populations. However, we are not yet 
their effects from those of water levels, 
water levels probably do still affect fish 
the river by creating changes in habitat qu 
effects can be modified by other factors an 
quanti f iable . 



ip now exists 
n the river, these 
les may be 
subsequently inter- 
lationship. For 
rces and water 
the above calcu- 
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able to sort out 
In short, while 
populations in 
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t quality 



Illinois Waterway Fish 19-94 



Aquatic Habitat Quality and Fish Populations 

The existing conditions of the bottomland lakes of the 
Illinois River have been described in detail earlier (Chapter 
4). They are being heavily impacted by suspended solids 
(turbidity) and sedimentation. Their average depth is anproxi 
mately 2 feet and the basins are saucer-shaped with floccu- 
lent ijottoms rather than solid substrates. As noted in 
Chapter 2, we could not predict any direct relationship 
between increased diversion and suspended solids concentra- 
tions in the middle and lower Illinois River, particularly 
in its off-channel habitats. If increased diversion is accom- 
panied by increased or unchanged suspended solids concen- 
trations in these reaches, the dominance of bottom- feeding 
fish in the river will continue. Major decreases in sus- 
pended solids concentrations would help sight- feeding fish 
compete with bottom- feeders for the limited food supplies 
of the river. All fish will be limited by decreases in the 
quantity of habitat caused by increased sedimentation, but 
the nest builders, such as sunfish, will be affected more 
than broadcast spawners, like carp and carpsuckers . In 
addition, the factors listed above related to decreased 
habitat quality will probably affect s ight- feeders and nest 
builders to a greater extent than bottom- feeders and broad- 
cast spawners . 

Finally, the poor habitat quality conditions in the 
bottomland lakes of the Illinois River will eventually extend 
to those additional habitat areas produced by increased diver- 
sion. The beneficial effects of increases in bottomland lake 
habitats on fish populations will only last while those habi- 
tats contain solid substrates for desirable game fish to 
spawn on. Although we cannot demonstrate conclusively 
how long this period will last, it should not be longer 
than several (3-5) years. 

If the diversion is increased for a few years, then 
decreased back to present levels, aquatic habitats will be 
degraded more rapidly than under the present diversion 
schedule. As explained in Chapter 4 (Surface Area and 
Volume of Bottomland Lakes in the Illinois River Valley), 
an increase in the depth of the lakes will increase sedi- 
mentation rates. Then, when diversion is reduced and water 
levels lowered, there will be even more mudflats and less 
water than under existing conditions. While the increase 
in mudflats will benefit shorebirds (see Chapter 9), there 
will be less habitat available for strictly aquatic species 
including fish. Increased sedimentation following increased 
diversion and increased water levels will probably occur not 
only in bottomland lakes, but in any slack water, including 



Illinois Waten^-ay Fish 19-95 



mainstem lakes, such as Peoria Lake, main channel borders, 
sloughs, and pooled areas immediatelv upstream from the 
navigation dams . 



SUMMARY OF IMPACTS 



The beneficial impacts of increased diversion on fish 
populations in the watenvay due to improved water quality 
conditions will primarily be exerted in the Chicago area 
reaches and the upper Illinois River. Both increased dis- 
solved oxygen concentrations and the dilution of toxicants 
will benefit the fish populations of these reaches. However, 
increased oxygen demands due to ammonia and, occasionally, 
resuspended sludge deposits will be extended further down- 
stream and may offset the dissolved oxygen increases that 
result from using Lake Michigan water for the diversion. 
In addition, the degree to which fish populations in the 
Chicago area reaches of the waterway will be enhanced 
due to water quality improvements will be limited bv the 
availability of quality habitats in this reach. 

Fish population in the middle and lower Illinois River 
will be beneficially impacted by increases in habitat quantity 
due to a permanent increase in diversion, but perhaDS onlv 
for a few years, until the bottom substrate in the additional 
habitats produced by increased diversion take on the same 
characteristic soft bottoms of the existing bottomland 
habitats and become unsuitable for spawning by nest-building 
species of fish. If diversion is increased and then reduced, 
there will be less aquatic habitat available than under 
existing conditions, because the rate of sedimentation will 
increase in slackwater areas as the depth increases, and 
less aquatic habitat and more mudflats will be available 
when water levels return to the existing regime. 



SECTION TV 

THREATENED AND ENDANGERED VERTEBRATES 
OF THE ILLINOIS WATERV.'AY 



CHAPTER 20: THREATENED AND ENDANGERED VERTEBR.i.TES 
OF THE ILLINOIS WATEPKAV 



K.U. Brigham, D. McCormick, K.S. Lubinski, 
and S .P . Havera 



INTRODUCTION 



Authority for listing species as threatened or endangered 
rests with the U.S. Fish and Wildlife Service and, in Illinois 
and Missouri, with the Illinois and Missouri Endangered Species 
Protection Boards. The following definitions apply: 

FEDERALLY ENDANGERED SPECIES - Anv species which is 
in danger of extinction throughout all or a signif- 
icant portion of its range, 

FEDERALLY THREATENED SPECIES - Any species which is 
likelv to become an endangered snecies within the 
foreseeable future throughout all or a significant 
portion of its range, 

STATE ENDANGERED SPECIES - Anv species which is in 
danger of extinction as a breeding species in 
Illinois and ^lissouri, and 

STATE THREATENED SPECIES - Anv breeding species which 
is likely to become a state endangered species 
within the foreseeable future in Illinois. (^'issouri 
does not list species as "threatened".") 

Article CXXXVIII of Administrative Order 1978 from the 
Illinois Department of Conservation presentlv is the onlv 
official list of threatened and endangered species recog- 
nized by the State of Illinois. Rule' 5 CSR 10-4.111, a' 
part of the Wildlife Code of Missouri, was established in 
1972 to list and provide certain statutory protection for 
the endangered species of Missouri. All listed species wliich 
are known or thought to occur in the project area (which in- 
cludes the Illinois Watenvay and the reach of the 'Mississippi 
River between Grafton and Alton, Illinois) are discussed 
below. In addition. Appendix C, Table C-15 summarizes the 
following information. It should be noted that no plants 
have been listed by the Illinois and Missouri Endangered 
Species Protection Boards. A preliminarv list has been 
drafted and public comment has been requested. Upon review 
of comments received, some or all of the species of plants 
on the preliminarv lists for Illinois and Missouri will be 
added to the official list of threatened and endangered snecies 



20 



FISHES 



Five species of fish occur in the project area that 
are listed as either threatened or endangered in Illinois 
or Missouri (I.D.O.C, 1978; Nordstrom, et.aL, 1977). No 
federally listed species are known or thought to occur in 
the project area. Illinois (I-D-O-C., 1978) lists no 
endangered species, but five threatened species in the 
project area: lake sturgeon, Acipenscr fulvescens ; alli- 
gator gar, Lepisosteus spatula ; cisco, Coregonus artedii ; 
blacknose shiner, Notropis heterolepis ; and bantam sunfish, 
Lepomis symmetricuF i In contrast, flissouri (Nordstrom, 
etal. , 1977) lists the lake sturgeon as an endangered 
species . 



Lake Sturgeon 

Originally the lake sturgeon occurred throughout the 
Ohio, St. Lawrence, and upper Mississippi River basins. 
It is now decimated throughout its range. Prior to 1880 
the species in Illinois was listed as very abundant from 
Lakes Calumet and Michigan and present in the Illinois 
and Mississippi Rivers. By 1908 it was considered rare 
in Illinois. Presently the lake sturgeon is known only 
from the lower Illinois River and from the Mississippi 
River upstream from its confluence with the Illinois. 

The lake sturgeon is a bottom-dweller with a 
preferred habitat of large rivers and the shallow waters 
of large lakes. Gravel and sand substrates are utilized 
primarily for feeding. SpavvTiing occurs in rocky shoals 
characterized by strong wave action. 

A major- factor in the decimation of the lake sturgeon 
was the blocking of migration routes to spawning beds by 
dams. These dams continue to restrict the movements of 
this species and, in conjunction with poor water quality, 
apparently serve as an effective barrier to its reinvasion 
of former range in the middle and upper Illinois River 
basin. It is unlikely that the lake sturgeon in the lower 
Illinois and Mississippi Rivers will be affected by 
increased diversion from Lake ^!ichigan. 

Alligator Gar 

The alligator gar ranges along the gulf coast of the 
United States from Florida to Texas. It penetrates up 



20 



the Mississippi River to central Illinois and enters the 
lower reaches of major tributary rivers. In Illinois, the 
alligator gar is known only from the Big Muddy, Illinois, 
Kaskaskia, and Mississippi Rivers. 

Virtually nothing is known about the life history of 
the alligator gar. Most records of the species are from 
rivers, but it has been taken in Horseshoe Lake and in 
Kaskaskia River oxbows in Illinois. In Louisiana it is 
reported to spawn from April through June. 

It is likely that the alligator gar has been extirpated 
from the project area. Thus, it will not be affected by 
increased diversion from Lake Michigan. 

Cisco 

The range of the cisco includes lakes throughout central 
and eastern Canada, the Great Lakes, and portions of the 
extreme upper Mississippi River basin. In the Great Lakes, 
it has been severely decimated by the sea lamprey and is 
apparently unable to compete sucessfully with the alewife. 
Illinois records of the species are from Lake Michigan, 
with a few strays down the Illinois River system as far as 
Meredosia. Presently the species is uncommon in Lake Michigan 
and extirpated from the Illinois River. 

The Cisco is a lake species, represented in rivers only 
by stray individuals. It spawns in early winter over sand 
or gravel substrates. Adult food ranges from plankton, 
especially large crustaceans, to small fish. Little else 
is kno\NTi of the life history of this species. 

The Cisco presently does not occur within the Illinois 
Waterway. Hence, it will not be affected adversely by 
increased diversion from Lake Michigan. It is unlikely 
that increased diversion will improve water quality in 
the Waterway sufficiently to permit the survival of stray 
individuals . 

Blacknose Shiner 

The range of the blacknose shiner includes most of 
the Ohio, St. Lawrence, and upper Mississippi River basins. 
It is disappearing from most of this area. In Illinois, 
the species formerly occurred throughout the northern 
two-thirds of the state. It now has become extirpated 
from all but some glacial lakes of Lake County and from 
a few tributaries of the Kankakee and Rock Rivers. 



20 - 4 



The habitat of the blacknose shiner ranges from clear, 
well-vegetated lakes to clear, sand-bottomed streams. Sketchy 
observations indicate that the blacknose shiner spawns 
during summer, and the small horizontal mouth suggests that 
it feeds on minute arthropods living among aquatic vegetation. 

The blacknose shiner has been extirpated from the 
Illinois Waterway, probably due to its intolerance of 
siltation and turbidity. It is still present in the basin 
of some small tributaries of the Kankakee River, but these 
areas are not within the region to be affected by increased 
diversion from Lake Michigan. 

Bantam Sunfish 

The bantam sunfish was described in 1883 from a collec- 
tion from the Illinois River at Pekin. No other specimens have 
been taken from the Illinois River. Presently the bantam 
sunfish occurs throughout the lower Mississippi River basin 
with its northern limit reaching southern Illinois. It is 
now known to occur in Illinois only at two localities in 
Union County. 

This fish is associated with swamps and bottomland 
lakes containing dense beds of vegetation in shallow water. 
Food items consist mostly of snails, crustaceans, and insects. 
Spawning occurs during late May. Sexual maturity is attained 
at 1 year, and the species lives just over 3 years. 

This species has been extirpated from the Illinois 
Waterway. Hence, it will not be affected by increased 
diversion from Lake Michigan. 



20 



AMPHIBIANS 



Two species of amphibians are listed as endangered in 
Illinois and one is listed as threatened. Of these, the 
threatened species (Illinois chorus frog, Pseudacris 
streckeri ) , occurs in the Illinois Waterway basin. No 
Illinois or Missouri endangered species or federally listed 
species are known or thought to occur in the project area. 

Illinois Chorus Frog 

The total knovsTi range of the Illinois chorus frog 
occupies four Illinois counties and a sand prairie in 
extreme southeastern Missouri. The range of the nominal 
subspecies extends from central Arkansas west and south 
through Oklahoma and Texas. In Illinois, this frog occurs 
in the sand prairies east of the Illinois River in Cass, 
Mason, Morgan, and Tazewell Counties. Attempts to find 
the frog in other sand areas of the state have been 
unsuccessful, although it may occur in the Iroquois/ 
Kankakee River basin. 

The Illinois chorus frog is known only from specimens 
taken during the breeding season; accordingly, its habitat 
is unknown. Smith (1961) notes that the species is abundant 
in the small area from which it is known and that during 
the breeding season (March) choruses can be heard continuously 
along the highways. 

The sand prairies occupied by this species are not 
within the area whose flood regime will be affected by 
increased diversion from Lake Michigan. Thus, the Illinois 
chorus frog will not be affected by implementation of the 
proj ect . . . 



20 



REPTILES 



Five species of reptiles are listed as endangered in 
Illinois and three are listed as threatened. Three of the 
endangered species (spotted turtle, Clemiiiys guttata ; slider, 
intermediate form between Pseudemys florida'na and P. concinna 
and Illinois mud turtle, Kmosternon flayescens ) and two of 
the threatened ones (western hognose snake, Heterodon 
nasicus and Great Plains rat snake, Elaphe guttata ) occur in 
the Illinois Waterway basin. The Illinois mud turtle is 
pending final rulemaking for addition to the federal list of 
endangered species. Presently, no reptiles on the federal 
or Missouri endangered species list occur in the project 
area. 



Spotted Turtle 

The range of the spotted turtle extends east from 
Illinois across the lower Great Lakes states to the Atlantic 
coast. Along the coast it ranges south from Maine to Florida 
This eastern species was not discovered in Illinois until 
1927 (Smith 1961) and is now recorded from southern Cook 
County in the vicinity of Wolf Lake and from Will County. 

Smith (1961) notes that almost nothing is known of the 
habits of the spotted turtle in Illinois. In northern 
Indiana the species is aquatic, inhabiting bogs. Cahn (1937) 
gives swamps and small weedy ponds with muddy substrates 
as the preferred habitat of the spotted turtle, but adds 
that the turtle frequently undertakes overland journeys 
of considerable length. 

The ponds from which the spotted turtle has been 
collected in Illinois are not within the area whose flood 
regime will be affected by increased diversion from Lake 
Michigan. Thus, the spotted turtle will not be affected 
by implementation of the project. 



Slider 

A large slider is associated with the major river 
valleys of southern Illinois. It is distinguished easily 
from the red-eared turtle, the only other species of 
Pseudemys known from the state, but its identity is uncertain 
Smith (1961) notes that introgress ion of P. f loridana genes 



20 



into the P. concinna populations of the lower Mississippi 
River valTey has produced an intermediate form. Thus, it 
is best to regard the southern Illinois sliders as hybrids. 

It should be noted that the taxonomy of the sliders 
is confused, even among specialists. Presently two genera 
( Chrysemys and Pseudemys ^ are used by some workers, while 
a single genus ( Chrysemys ) is used by others. The genus 
Pseudemys is used here in reference to the endangered slider 
because it is listed under that name by the Illinois 
Endangered Species Protection Board and by Cahn [1937) and 
Smith (1961), the principal works on the turtles of Illinois. 

This hybrid slider is restricted to the lower Mississippi 
River valley. The total range of the parental species in the 
United States extends from the Atlantic coast west to western 
Texas and from the Gulf of Mexico north, in the lowland 
areas, to Illir; is and Virginia. The hybrid is very rare in 
Illinois and is restricted to the large rivers and adjacent 
lakes in southern Illinois. The northernmost records are 
Mount Carmel , on the V.'abash River, and Elsah, on the 
Mississippi River (Smith 1961). 

This turtle is an aquatic species which leaves the water 
only to bask on logs or to lay eggs. As stated above, the 
hybrid apparently is restricted to the large rivers and 
adjacent lakes in Illinois. Elsewhere it is associated 
with abundant aquatic vegetation, shallow water, and a soft 
substrate. ^^Tiile associated with large rivers, the turtles 
are taken most frequently in backwaters and sluggish side 
channels rather than in the main channel. 

Although the habitat of the slider in the project area 
may have its flood regime altered by increased diversion 
from Lake Michigan, it is not anticipated that this will 
affect adversely populations of this turtle. 

Illinois Mud Turtle 

The Illinois mud turtle occurs in northeastern Missouri 
and southeastern Iowa adjacent to the Mississippi River, 
but the greatest part of its range is in Illinois. Other 
subspecies occur in the Great Plains and southwest from 
Nebraska south to Arizona and Texas. In Illinois, it is 
known from Henderson, Lee, and Whiteside Counties along the 
upper Mississippi River, east of the Illinois River from 
Morgan to Peoria Counties, and from Illinois Beach State Park 
in Lake County. The latter population was unknown until 1966 
and presently is documented by only two specimens. 



20 - 



This turtle is confined to sand prairies. Its preferred 
habitat is shallow sand prairie ponds, but it also may occur 
in backwater sloughs of major rivers. The species is highly 
aquatic and spends much of its time lying partially buried 
in the soft material of the pond substrate. 

The sand prairies occupied by this species are not 
within the area whose flood regime will be affected by increased 
diversion from Lake Michigan. The backwater sloughs along 
the Illinois River, however, are likely to be affected. 
Philip W. Smith (pers. comm.), Illinois Natural History 
Survey, Urbana, believes that the Illinois River population 
of this turtle is confined to the ponds in Sand Ridge State 
Park. The only river backwater specimens known to him are 
from the upper Mississippi River. Smith noted a recent study 
(1977, unpublished) of the Sand Ridge area which estimated 
the Illinois mud turtle population at 10 turtles. If this 
species is confined to Sand Ridge State Park, it will not 
be affected by implementation of the project. 

The U.S. Fish and Wildlife Service currently is 
reviewing the status of this turtle for possible recognition 
as a federally endangered species. Proposed critical habitat 
consists of an area in Iowa and a circular area with a radius 
of one mile centering in Mason County, Illinois. The area 
in Illinois is near, but not within the floodplain of the 
Illinois Waterway. 

Western Hognose Snake 

'''he T'^nge of the western hognose snake is disjunct. 
In * d States, the main portion of the range lies 
easi ci ... Rock)' Mountains as far east as western Minnesota, 
Iowa, and Mi$souri, from Canada to Mexico. Other populations 
occur in central and northwestern Illinois and in south- 
eastern Missouri. In Illinois, its range is a series of 
small, scattered relicts of a formerly widespread occurrence 
(Smith 1961). Specimens are known from Carroll, Henderson, 
Mercer, and Rock Island Counties along the ^5ississippi 
River; from Lee County; and from Tazewell to Morgan Counties 
along the east ban): of the Illinois River. 

This '^nake is confined to sand prairies. It spends 
much of tine foraging for toads in open sand and in 
adjacer jodlots. Most specimens have been found crossing 
sandy x is or in brushy or weedy sites in sand prairies. 
The species is seldom found beneath objects. 



20 -9 



The sand prairies occupied by this species are not 
vithin the area whose flood regime will be affected by 
increased diversion from Lake Michigan. Thus, the western 
hognose snake will not be affected by implementation of 
the project. 



Great Plains Rat Snake 



This snake occurs throughout the southern half of 
the United States east of Arizona, except for a hiatus 
roughly along the lower Mississippi and Ohio Rivers. The 
eastern and western populations are recognized as distinct 
at the subspecies level. Six specimens of the Great Plains 
rat snake are extant from Illinois localities. All are 
from the Mississippi River floodplain from Jersey to 
Monroe Counties. 

Little is known of the life history of the Great 
Plains rat snake. Four of the Illinois specimens were 
found dead on a road bordered on one side by heavily 
farmed Mississippi floodplain and on the other side by 
dry, precipitous rock bluffs. Two other specimens were 
taken on the forested campus of Principia College (Smith 
1961). 

Illinois habitat from which this species has been 
taken includes Mississippi floodplain downstream from the 
Illinois River. This floodplain, however, is protected 
from flooding by levees. In addition, the Great Plains 
rat snake apparently occurs only in the portions of the 
floodplain immediately adjacent to the bluffs. Thus, it 
is unlikely that the species will be affected should the 
project be implemented. 



20 



10 



BIRDS 

The Illinois Endangered Species Protection Board lists 
breeding populations of 33 species of birds as endangered and 
seven as threatened in Illinois. Of these, four are on 
the federal list of endangered species. Thirty-one of the 
state endangered species, including two of the federal en- 
dangered species, and the seven state threatened species 
are known or likely to occur in the project area. Five 
species listed as endangered in Missouri are thought to 
occur within the confines of the project area in St. Charles 
County. Only one of these species is listed as endangered 
exclusively by Missouri. These total 39 species group 
conveniently into four categories on the basis of their 
utilization of waterway habitat and are discussed, by 
category, below. Each species is identified by an accompany- 
ing letter as to its status, where E = state endangered 
species, T = state threatened species, and * = federally 
endangered species. 

Bachman's warbler ( Vermivora bachmanii ) is listed as 
endangered in Illinois by the Illinois Endangered Species 
Protection Board. It also is listed as endangered by the 
U.S. Fish and Wildlife Service. Its inclusion on the list 
of Illinois avifauna, however, may be speculative. Sight 
records for the species in Illinois date from the late 
1800's. These all lack satisfactory documentation and have not 
been accepted as valid (see Bohlen (1978:105) for a discussion 
of the literature regarding this matter). A single specimen 
was reported by Smith (1941) as having been taken from 
Decatur in 1899, but the specimen can not be located. 
Bohlen (1978:105) questions whether or not it ever existed. 
Ue adds that the species might have occurred as an over- 
migrant in Illinois when its population was greater; or 
might have been a summer resident in southern Illinois. 
He lists the species for Illinois, but relegates it to 
hypothetical status. Dr. Richard Graber (Illinois Nat. Hist. 
Surv. , pers. comm. ) also notes that no valid records exist 
for Bachman's warbler in Illinois. He adds that it probably 
once occurred here, but that if it did, it now has been 
extirpated from the state and may even be extinct. The 
present report does not consider Bachman's warbler as likely 
to occur in the Illinois waterway basin. 

Seventeen species of birds known from or likely to occur 
in the project area would probably not be associated with 
waterway habitat. Included here are Cooper's hawk, Accipiter 
cooneri (E) ; red-shouldered hav.'k, Buteo lineatus (E) ; Swainson's 
hawk , B . swainsoni (E) ; sharp- shinned hawk, Accipiter striatu? 
(E) ; marsh hawk. Circus cyaneus (E) ; yellow rail, CoTurnicors | 
noveboracensis (E) ; Eskimo curlew, Numenius borealis (E, *) ; 



20 - 11 



upland sandpiper, Bartrania longicauda (E) ; barn owl, Tyto 
alba CE) ; long-eared owl, Asio otus (E) ; short-eared owl , 
A. flanipeus (E) ; brown creeper, Certhia familiarus CE) ; 
Fachnan's sparrow, Aimophila aestivalis (EJ ; Bewick's wren, 
Thryornanes bewickii (T) ; lo;:gerhead shrike, Lanius ludovicianus 
(T) ; Brewer's blackbird, Eupha^us cyanocephalus (T) ; and 
Henslow's sparrow, Amnodramus henslowii [T) . 

Of the remaining 22 species of birds, two are associated 
with bottomland forest habitats. These are the veery, 
Catharus fuscescens (T) , and Swainson's warbler, Linothlypis 
swamsonii (T) . TFe veery is a common migrant in spring, an 
uncommon migrant in autumn, an occasional summer resident in 
the upper part of the waterway, and a very rare summer resi- 
dent in the central part of the waterway. Swainson's 
warbler is an occasional migrant and summer resident in the 
southern portion of the waterway and a very rare vagrant in 
the remainder of the waterway basin. 

A second group of birds associated with the waterway 
and adjacent habitats includes four large predators: the 
Mississippi kite, Ictinia mississippiensis (E) ; bald eagle 
Haliaeetus leucocephalus (E,*); osprey, Pandion haliaetus 
CE) ; and peregrine falcon, Falco peregrinus CE,*Ti The 
Mississippi kite is an uncommon migrant and local summer 
resident along the ^^ississippi River in southern Illinois and 
is only a very rare vagrant in other portions of the state 
CChapter 11). The bald eagle is a fairly common migrant and 
winter resident along the Illinois and Mississippi Rivers 
CChapter 11). It formerly nested in Illinois. The osprey i? 
an uncommon migrant which also formerly nested in Illinois. 
The peregrine falcon once was a fairly common migrant and 
rare summer resident in Illinois, but now is an occasional 
migrant along Lake Michigan and a rare migrant in the 
remainder of the state. 

Six species of birds associated with the waterway and 
adjacent large floodplain lakes are found in shoreline and 
mud flat habitats. Included here are the piping plover, 
Charadrius melodus CE) ; Wilson's phalarope, Steganopus 
tricolou rs); Forster's tern, Sterna forsterl CE) ; common 
tern, S. hirundo CE) ; least tern, S. albifrons CE) ; and 
black tern, ChTidonias niger CE) Chapter 9). The piping 
plover is a very rare summer resident along Lake Michigan 
and a rare migrant elsewhere in the state. Wilson's 
phalarope is an uncommon migrant throughout the waterway 
and formerly nested in northeastern Illinois. Forster's tern 
is a common' migrant along the waterway and an occasional 
summer resident in northeastern Illinois. The common tern is 



20 - 12 



a comnon migrant and rare summer resident on Lake Michigan. 
It is a fairly common migrant in the remainder of the state. 
The least tern is a rare summer resident in central Illinois 
and a rare migrant with post-breeding wanderers in the 
remainder of the state. Formerly this species was a rare 
summer resident in northern Illinois . The black tern is a 
common migrant along major lakes and rivers throughout 
Illinois. It is a common summer resident in the north, but 
a rare summer resident in central Illinois. 

The 12 species just discussed are associated with 

waterway habitat and it is likely that a change in water 

regime would affect their populations. Perhaps the greatest 

impact would result from inundation of mud flats and bottom- 
land forest. 

The remaining 10 species include principally the larger 
wading birds (herons and egrets, Chapter 10) and a few other 
species intimately associated with wetlands. There are the 
double-crested cormorant, Phalacrocorax auritus (E) ; snov.y 
egret, Eeretta thula (E) ; great egret, Casnerodius albus (E) ; 
little blue heron, Florida caerulea (E) ; American bittern, 
Botaurus lentiginosus (,EJ ; black-crowned night heron, 
NycticoTax nycticorax (E) ; black rail, Laterallus jamaicensis 
(FJ ; purple gallinule, Porphyrula martinica (E) -"common 
gallinule, Gallinula chloropus TT)~, and yellow-headed black- 
bird, Xanthoccphalus" xanthocephalus (E) . Some of these arc 
much more likely to be affected by an altered water regime 
than the species discussed above. A discussion of their 
status follows. 

The double-crested cormorant is an uncommon migrant 
along the Mississippi and Illinois Rivers and a rare 
summer resident along the upper Mississippi River (Chapter 11) 
It is an occasional migrant in the remainder of the state. 
The species formerly was a common migrant and uncommon 
summer resident along the Illinois River, but began a 
significant decline since the 1950's. The preferred habitat 
of the double-crested cormorant is large lakes and rivers. 
If present, individuals may be seen perched on snags and 
branches near or in the water. It is not likely that an 
altered water regime in the Illinois Waterway will affect 
adversely this species. 

The sno^sy egret is a rare migrant and postbreeding 
wanderer in Illinois, but may be a rare local summer 
resident. The species is found near ponds and sloughs. 



20 - 13 



The great egret is a common migrant and summer resident 
along the Illinois and Mississippi Rivers and a few other 
areas where nesting colonies are present. It is an 
uncommon migrant and postbreeding wanderer in the remainder 
of the state. The preferred habitat of the great egret is 
along rivers, lakes, and sloughs. 

The little blue heron is a common migrant and summer 
resident in southern Illinois, an uncommon migrant and 
postbreeding wanderer in central Illinois, and an occasional 
migrant and postbreeding wanderer in the remainder of the state, 
Typically, it is found around shallow pools and sloughs. 

The American bittern is an uncommon migrant and a rare 
summer and winter resident in Illinois. The species 
appears to be on the decline in the state. It is found in 
marshes and swamps. 

The black-crowned night heron is a fairly common 
migrant, an uncommon summer resident and a rare winter 
resident in Illinois. Nesting colonies appear to be 
decreasing in numbers. The species is found in swampy or 
marshy areas. 

The five species of herons and egrets discussed above 
may be affected adversely by an altered flood regime in the 
Illinois Waterway (Chapter 10). The effects would be most 
severe on those species still breeding along the waterway 
(great egret and black-crovmed night heron). Under the 
present water regime, temporary pools are created adjacent to 
the river during high-water periods. Fishes are carried into 
these pools with the floodwaters. The drying of these pools 
coincides with the hatching period of the herons and egrets. 
The fishes in the drying pools become increasingly vulner- 
able to predation by birds as the waters become shallower 
and the pools -shrink in size. This concentrated food source 
may be critical to the survival of the nestlings. An 
altered water regime may affect these pools. Too much 
water or water too late in the season may preclude or 
delay the drying of the pools. Thus, the fishes would not 
be as available to the herons and egrets and survival of the 
young birds would be reduced. 

The black rail is a rare migrant in Illinois and a rare 
summer resident in the central and northern portions of the 
state. This species stays in wet grasses, rushes, and sedges 
and is the most difficult of the rails to flush. It is 
likely that an altered water regime in the Illinois Waterway 
would displace the habitat of this species laterally result- 



20 - 14 



ing in a reduction of habitat. Timing of high-water periods 
is not likely to inundate nesting sites of this species, 
however, as the last evidence of nesting by black rails in 
Illinois was in 1932. 

The purple gallinule is a very rare spring migrant in 
Illinois and a very rare summer resident in southern portions 
of the state. It is found in marshy or swampy areas, 
particularly those with lotus. Only three or four recent 
records exist for this species in the project area, as 
Illinois is on the extreme northern portions of its range. 
It is unlikely that the status of this species in Illinois 
would be affected by an altered water regime in the Illinois 
Kater\say . 

The common gallinule is an uncommon migrant and locally 
common summer resident in northern Illinois and an occasional 
migrant and summer resident in central and southern portions 
of the state. The species is found in marshy areas and la];es 
and is known to nest CBohlen, 1975:49) along the Illinois 
V.'aterway. It is possible that unfortunate timing of high- 
water periods with an altered water regime may inundate 
nesting sites of this species. 

The yellow-headed blackbird is a locally uncommon 
migrant and summer resident in northern Illinois and a rare 
migrant in the remainder of the state. It is found in 
marshes, feedlots, and pastures and appears to be declining 
in the north. This species is not likely to be affected by 
an altered water regime in the Illinois V.'aterway. 



2^ - 15 



MAJCIALS 



Two species of mammals known or likely to occur 
in the project area have been recognized as endangered in 
Illinois by the Illinois Endangered Species Protection 
Board. These species, the gray bat ( .Vyotis grisescens ) 
and Indiana bat (?j sodalis ) , also arc'listea as endangered 
by the U.S. Fish a d Wildlife Service. Two additional species 
occurring in the project area, the river otter ( Lutra 
canadensis ) and the bobcat ( Lynx rufus ) are listec as threat- 
ened in Illinois by the Illinois Endangered Species Pro- 
tection Board. No Missouri endangered species are found 
in the project area. 

Very few documented records for these mammals exist 
for Illinois. Hoffmeister and Mohr (1957) reported the 
gray bat from Hardin and Pike Counties; the Indiana bat 
from Hardin, Jo Daviess, and LaSalle Counties; and the 
river otter from about 25 counties throughout all but 
northeastern Illinois. The bobcat is thought to occupy 
heavily wooded habitat along the major rivers of southern 
Illinois and may exist in the southernmost reaches of the 
project area. However, Hoffmeister and Mohr (1957:123) do 
not record specific sightings of the cat in the project 
area. Preferred bat habitat in the project area includes 
cement mines in LaSalle County and the Indiana bat has beer. 
collected there. Both bat species spend their summers in tree 
roosts, usually in trees with a diameter of 18 inches or 
greater and which overhang the water. This habitat occurs 
throughout the entire waterway, but actual use by the bats 
has not been investigated. A similar lack of data exists for 
the river otter. In view of the lack of specific inventory 
data for these four mammal species along the Illinois Water- 
way, it is not possible to assess the potential impacts 
upon them from an altered water regime in the waterway. 

ADDITIONAL IKF0R!1ATI0N ON ENDANGERED SPECIES 

In addition to Chapter 11 which is devoted to bald 
eagles, double-crested cormorants, and Mississippi kites, 
a listing of and pertinent information on threatened and 
endangered fishes, amphibians, reptiles, birds, and mamnals 
that could occur in the project area are presented in 
Appendix C-13. 



20 - 16 



SmUIARY OF EFFECTS OF INCREASED DIVERSION 

Five species of fish, one amphibian, and five reptiles 
occur or have been collected in the project area and are 
currently listed as either threatened or endangered. 
None of these species should be affected by increased 
diversion. 

Seventeen species of threatened or endangered birds 
in the project area, including five hav/lcs, one rail, two 
shorebirds, three owls, and six passerines, are not asso- 
ciated with waterway habitat and would not be affected by an 
increased diversion. Two threatened species of passerines 
(the veery and the Swainson's v/arbler) associated with 
bottomland forest may be slightly affected in local areas 
where bottomland forest is flooded. The effects of increased 
diversion upon four endangered raptors (Mississippi kite, 
bald eagle, osprey, and peregrine falcon) and six endangered 
shorebirds (piping plover, V.'ilson's phalarope, Forster's 
tern, common tern, least tern, and black tern) that are 
closely associated with the waterway are difficult to pre- 
dict. Small numbers of endangered double-crested cormorants 
are intir.ately associated with the waterway during migration 
but it is not likely that an altered water regime will have 
an adverse effect upon this species (Chapter 11). An 
increased diversion may adversely affect five endangered 
species of herons and egrets (sno\%'y egret, great egret, little 
blue heron, American bittern, and black-crowTied night heron). 
Effects would be most severe on the great egret and black- 
crowned night heron that continue to breed along the water- 
v.'ay and rely upon the drying of pools in acquiring food for 
their young (Chapter 10). Of the three endangered species 
of rails that occur in the project area, the black rail and 
the common gallinule would be adversely affected by a reduc- 
tion in habitat that would probably result from an increased 
diversion. The third rail species (purple gallinule) and 
an additional passerine species (yellow-headed blackbird) would 
be unaffected by an altered water regime in the Illinois 
Waterway. 

Because of the lack of specific inventory data for 
the two species of threatened (river otter and bobcat) and 
the two species of endangered (gray bat and Indiana bat) 
mammals thought to occur along the Illinois V.'aterway, no 
feasible assessment of the potential impacts of increased 
diversion on their populations can be made. 



SECTION V 



SUWURY OF EFFECTS OF INCREASED DIVERSION 



CHAPTER 21: Sl'TlARY OF EFFECTS OF INCREASED DnTRSION 



Chapter 4. Surface Area and X'oluinc of Bottomland LaVe^ in 



the Illinois River Vallev 



The average increase in v.-ater levels 


that w 


from the proposed 6,6n0-cfs diversion 


at 


both He 


Pool) and Havana (La Orange Pool) would 


be 


n . 5 2 m 


The average increase in water levels f 


or 


the 10, 


diversion at Henry and Havana would be 


. 


8 5 m (2 


0.73 m (2.4 ft), respectively. In the 


Peoria Po 


6,600- and 10,non-cfs diversion would 


enl 


arge th 


area of water in the bottomland lakes 


by 


at leas 


ha (5,942.9 acres) during late summer 


and 


e a r 1 %• 


addition, an unknown amount of bottoml 


and 


forest 


inundated. In the La Grange Pool, the 


6 , 


600- an 


cfs diversion would increase the water 


surface a 


land lakes by approximately 4,058.3 ha 


(9 


,974 .5 


7,752.4 ha (19,099.1 acres), respectively 


Incr 


during late summer and fall would resu 


It 


in the 


of the surface area of bottomland lake 


s b 


y sub me 


that would normally form mud flats. 







ould result 
nry (Peoria 

(1.7 ft ) . 
000- cfs 
.8 ft) and 
ol, both the 
e surface 
t 2,406.0 
fall. In 

would be 
d 1 , M - 
rea of bottom- 
acres) and 
eased diversion 
enlargement 
rging areas 



In Peoria Pool, the proposed 6,600- or 10,non-cfs diver- 
sion would increase the volume of the bottomland lakes at 
low water by at least 2,647.7 acre-feet and the water level 
would be above the tree line. Although substantial increases 
in volume would occur above the tree line, the magnitude of 
these increases could not be estimated. In La Grange Pool, 
a diversion of 6,6n0-cfs would increase the volume bv a^out 
26,000 acre-feet. A 10,000-cfs diversion would increase the 
volume by 40,551.7 acre -feet. 

The average depth of the bottomland lakes would increase 
proportionately with increases in water levels resulting 
from diversion. 

The proposed increased diversions would have the least 
impact upon the surface area and volume of the Upper Pools 
of the Illinois River valley. The surface area and volume of 
the Peoria Pool would be preatlv affected bv increased diver- 
sion because most of its bottomland lakes are directly con- 
nected with the ri^'er. In La Grange and Alton pools, natural 
and man-made levees buffer bottomland areas from some of the 
changes in river levels; and, therefore, the effect oi' in- 
creased diversion on the bottomland areas in these pools m3\- 
be less than in the Peoria Pool. 



21- 2 



Chapter 5. Vege t ation ^ 

Bottomland Forest 

Permanent flooding of the bottomland community would 
result in the death of the inundated '.soody species in 
congruence with their inherent water tolerances. Continuous 
flooding during the growing season from May to October be- 
comes damaging for periods over 2 weeks in duration for water- 
sensitive species. The critical depth of water appears to be 
the level (less than 51 cm or 20 in) that covers the root 
crowns of the trees. Thus, a small amount of water for 
periods longer than 2 weeks can begin to change the bottom- 
land forest communities. The longer the duration of inun- 
dation, the greater the magnitude of damage. Inundation for 
half or more of the growing season during 4 to 8 consecutive 
years will practically eliminate the majority of bottomland 
tree species . 

At Henry in the Peoria Pool, the 6,600-cfs diversion 
would have increased water levels an average of 0.27 m (0.9 
ft) above the tree line for the 30 April-1 October growing 
season in 1971, an average of 1.13 m (3.7 ft) above the 
tree line in 1973, and an average of 0.43 m (1.4 ft) above 
the tree line in 1977. The 10,000-cfs diversion would have 
overtopped the tree line at Henry by 0.70 m (2.3 ft) during I 
this growing period in both 1971 and 1977. Consequently, 
both of these proposed diversion rates would have inundated 
bottomland forest, consisting mainly of silver maple, cotton- 
woods, elms, ash, and willow trees, and would have had 
deleterious effects during the same growing season on all 
but the willows. These negative effects would be compounded 
if the inundation would occur in consecutive growing seasons. 

At Havana in the La Grange Pool, the proposed increased 
diversions -would not have resulted in as much inundation. 
Only the 6,600-cfs diversion in 1973 resulting in an average 
increase of 1.16 m (3,8 ft) above the tree line and the 
10,000-cfs diversion in 1977 resulting in an average increase 
of 0.12 m (0.4 ft) above the tree line would have inundated 
bottomland forest. Thus, bottomland forest communities in 
the La Grange Pool would not have been as drastically affected 
by the increased diversions as those in the Peoria Pool. 
The 1.16-m (3.8-ft) increase above the tree line as a result 
of the 6,600-cfs diversion in 1973 would have had devastating 
effects on the bottomland forest communities. The increase 
of 0.12 m (0.4 ft) above the tree line by the 10,000-cfs 
diversion in 1977 would have had more limited detrimental 
effects on most bottomland tree species. 



Shrubs 

A ma3ority of the shrubs in the bottomlands within the 
project area are young trees and the tolerances of these voung 
trees to higher water levels are somewhat similar to their 
tolerances as older individuals. Henerally, black willov, 
water locust, buttonbush, and swamp priv^et are probablv 
the most water- tolerant shrubs or small trees depending 
upon flooding duration, frequency, depth, and other associated 
factors. Continuous flooding during the growing season of 
May through October for lengthv periods or frequent flooding 
may reduce the number of species in the shrub strata as well 
as in the overstory. 

Herbaceous Vegetation -- Forbs and Grasses 

The water tolerances of herbaceous plants vary among 
species, but thev appear to be more sensitive to high water 
conditions than shrubs and trees. Relatively short period? 
of flooding during the growing season are injurious to 
terrestrial herbs. Increased water levels via diversion 
would be detrimental to the majority of the herbaceous and 
grass species existing in the floodplain if the water level? 
were increased during the growing season and inundation 
lasted 2 weeks or longer. Diversion during the non-growinc 
season of herbaceous vegetation should have reduced detri- 
mental effects except for those caused by deposition of silt 
and deb ri s . 

Wetland Vegetation -- Emergent, Submergent, and Floating 
Aquatic 

Turbidity ha? limited the growth of emergent, submergent, 
and floating aquatic plants in the Illinois ^'allev bv inhibiting 
the sunlight necessary for photosynthesis from reaching the 
plants. Sedimentation has filled shallow areas that formerlv 
supported aquatic vegetation. In addition, sedimentation 
has created a soft flocculent bottom that covers the original 
firm substrate, making it difficult for marsh and aquatic 
plants to gain or retain a foothold. Therefore, these plant? 
are easily uprooted by wave and rough fish agitation. 

During the three studv year? m the Peoria Pool, the 
6,600- and 10 ,000-cfs diversion would have resulted in a 
minimum rise in water levels of 0.27 m (0.9 ft) above the 
tree line. Increases of this magnitude would have resulted 
in water levels too deep for the growth of submergent, 
emergent, and floating aquatic plants in most of the lake 
basins. New shallow areas for wetland plant growth would 
eventually become available as bottomland timber began to 
die. 



:i-4 



In La Grange Pool, the 6,600-cfs diversion would not 
have raised water levels above the tree line during 19"1 and 
1977, but bottomland forest inundation would have occurred 
in 1973. The 10,n00-cfs diversion would have inundated 
bottomland forest in 1977, but not in 1971. Increased 
diversion during the years in which bottomland forests were 
not flooded, however, may have inundated additional shallow 
areas for growth of aquatic plants. 



that 

aqua 

of t 

tion 

aqua 

bott 

unti 

for 

woul 

and 

deep 

dimi 



Inc 
wou 
tic 
he s 
wou 
tic 
omla 
1 th 
thes 
d al 
floa 
er, 
nish 



reas 
Id b 
plan 
oft 
Id p 
plan 
nd t 
e bo 
e pi 
so h 
ting 
the 
ed, 



ed d 

e po 

ts . 

floe 

reel 

ts i 

imbe 

ttom 

ants 

ave 

aqu 
amou 
ther 



iver 
tent 

How 
cule 
ude 
n th 
r CO 

bee 

to 
a de 
ati c 
nt o 
ebv 



si on wo 
ial hab 
ever, t 
nt bott 
the dev 
ese new 
uld pos 
ame too 
remain 
triment 
plants 
f sunli 
inhib i t 



uld crea 
itat for 
urbi di tv 
om by wa 
elopment 

areas . 
s i b 1 >• s u 

f loccul 
rooted . 
al effec 
. As th 
ght reac 
i n g grow 



te new shall 

subme rgent 

caused by t 

ve and rough 

of submerge 

Firm substr 

pport emerge 

ent from sed 

Increased w 

t on existin 

e water dept 

hing these p 

th and germi 



ow areas 

and floating 
he resuspension 

fish agi ta- 
nt and floating 
ate in flooded 
nt vegetation 
imentati on 
ater levels 
g submergent 
h became 
lants would be 
nation . 



Wetland \'egetation 



Moist-Soil Plants 



The recession of river levels during the warm summer 
months exposes mud flats along the shores of bottomland lakes 
in the Illinois River valley that are pioneered by moist- 
soil plants. These plants are a vital food source for 
waterfowl as they migrate through the Illinois Valley in the 
spring and fall . 

The abundance of mud flats in the Illinois River vallev 
is regulated by the difference in elevation between low water 
levels and the tree line in the bottomland lakes -- the 
lower the lake level, the greater the exposure of mud flats 
in the lake basin. Moist-soil plant development is governed 
by the duration of low water during the growing season. 
Small rises in water levels during the growing season ma^• 
inundate and destroy extensive areas of moist-soil plants. 
The extent of mortality depends upon the height of the water 
rise and the lateness in the growing season. Once these 
plants arc destroyed bv a brief inundation, they mav not 
have sufficient time to become re- es t abl ished . 



The distance between the tree line in Peoria Pool and 
the lowest average water level during t^e in July-1 October 
growing season is only 0.34 m (1.1 ft). Water level increases 
in the Peoria Pool as a result of the proposed 6,6nO-cfs 
diversion would have raised water levels from between n.OP m 



21-5 



(0,5 ft) to 0.55 m (1.8 ft) above the tree line during 
1971, 1973, and 1977, thus completely inundating all of the 
mud flats. The 10,000-cfs diversion would have also flooded 
all of the mud flats by raising water levels 0.61 m (2.0 ft) 
and 0.85 m (2.8 ft) above the tree line during 1971 and 
1977, respectively. 

The distance between the tree line in La Grange Pool 
and the lowest average water level during the 10 Julv- 
1 October growing season is 1.22 m (4 ft). Water level 
increases as a result of the 6,600-cfs diversion in 1971 
in La Grange Pool would have reduced the area of mud flats 
by 61. 4o and completely inundated all of the mud flats during 
1973 and 1977. The 10,000-cfs diversion would have reduced 
the area of mud flats during lO^l by 75.8'!.. In 19"7, the 
10,000-cfs diversion would have raised water levels 0.27 m 
(0.9 ft) above the tree line thereby completely inundating 
all mud flats in the La Grange Pool. 



Chapter 6. Waterfowl Hunting Areas 




The Illinois Department of Conservation issued 


li censes 


to 272 private duck hunting clubs that managed land 


alonq 


the Illinois River during 19:'7. Peoria (11,129 ha; 


27 ,4^9 


acres) and La Grange (12,371 ha; 30,569 acres) pool 


contained 


87.3^0 of the total 26,905 ha (66,482 acres) owned bv 




licensed duck clubs in the Illinois Valley. A questionnaire 


sent to 219 duck clubs that owned 16 hectares (40 acresl 


or more along the Illinois River indicated that 32o 


of the 


responding duck clubs could control water levels on 


thei r 


property. The U.S. Fish and Wildlife Service and th 


,e Illi- 


nois Department of Conservation own 20,428 hectares 


(5n ,4-S 


acres) in the Illinois River valley containing 9,853 


i hectares 


(24,344 acres) of water. Water levels can be manage 


'd on 


14.61 of the total area. Thus, state, federal, and 


p r i \- a t e 


areas control about 36,758 ha (90,829 acres) that arc used 


primarily for waterfowl hunting and management, representing 


approximately 43.2°o of the 85,020 ha (210, OOn acre?) 


of 


nonleveed floodplain in the Illinois X'alley. 





Increased water levels resulting from the proposed 
6,600-cfs diversion during the 10 Julv-l October growing 
season for three study years (19^1, 1973, and 19"7) in 
Peoria Pool would have inundated during 1973 and 1977 approx- 
imately 4.4'c (103 ha; 254 acres) of the leveed private duck 
clubs that responded to our questionnaire. The 10,000-cfs 
diversion would have inundated during 19'"1 and 1977 approxi- 
mately 12. 01 (279 ha; 689 acres) and 20.61 (480 ha; 1,18" 
acres), respectively, of leveed areas of duck clubs responding 
to our questionnaire. 



21-6 



In La Hrange Pool, increased water levels as a result \ 
of the 6,600-cfs diversion would have inundated 0.4° (16 
ha; 40 acres) during 1971 and 9 A% (335 ha; 827 acres) 
during 1973 and 1977 of responding leveed duck clubs. No 
state or federal land would have been flooded. The 10,000- 
cfs diversion during 1971 and 1977 would have inundated 
approximately 5.0°o (195 ha; 482 acreM and 14.9^o (531 ha: 
1,312 acres), respectively, of the land belonging to responding 
duck clubs. The 10,000-cfs diversion would have also inundated 
22.7-0 (413 ha; 1,022 acres) of the state and federal property 
in La Grange Pool . 

In addition to flooding leveed waterfowl impoundments, 
higher water levels as a result of increased diversion would 
impede the flow of water out of leveed waterfowl areas making 
it difficult or impossible to achieve the drawdown of Avater 
necessary for the growth of moist-soil food plants. 

Chapter 7. Waterfowl Populations 

To varying degrees, abundance of dabbling duck specie? 
is determined by the availability of moist-soil plant food?. 
The abundance of moist-soil plants is regulated hv low water 
in midsummer, and their seed availability to ducks is governed 
by water levels that are slightlv above normal during the 
fall. The proposed increased diversions could eliminate moist- 
soil plants in the Peoria Pool and greatly reduce those in 
the La Grange Pool. This loss of moist-soil plant resource? 
would be particularly detrimental to dabbling duck population? 
during the fall. Pintails, green-winged teal, and blue- 
winged teal numbers would decline drastically. The abundance 
of mallards, the most important duck in the Illinois Valley, 
would decline, but currently not to the extent of other 
dabb lers . 

Diving -duck numbers should not be adversely affected by 
an increase in summer and fall water levels from diversion. 
They feed primarily on animal life that might not change 
greatly in abundance with an increase in water levels. 
Canada geese and snow geese feed almost entirely in field?, 
thus utilizing little of the native food plant resources. 
Therefore, their abundance should not be influenced by anv 
change in water levels. 

The proposed increased diversions during the spring 
would probably not be detrimental to waterfowl and may make 
other food resources available to waterfowl. 



I 



21-:' 



Chapter 8. Waterfowl Harvest 

The diversion of 6,600 cfs or 10,000 cfs of Lake Vichi- 
gan water into the Illinois River would have a deleterious 
effect upon the harvest of waterfowl. This effect would 
occur through a reduction in the natural food resources. 
The 6,600-cfs diversion would eliminate the appearance of mud 
flats in the Peoria Pool, therebv eliminating the production 
of moist-soil plant foods. The adverse effect of the 6,60n- 
cfs would not be quite as great in the La Grange or Alton 
pools because these lake beds are higher in relation to the 
river level. Nevertheless, only in an occasional vear 
would the 6,600-cfs diversion schedule expose limited mud 
flats in these pools; at the 10,000-cfs diversion rate, the 
area of mud flats would he further restricted. 

We believe that the elimination of moist-soil food 
resources for waterfowl in the Illinois Valley would reduce 
the duck harvest by 40 to 50o. Currently, the mallard kill 
would not decline as greatlv as other dabblers because part 
of its food supply is obtained from waste grain in harvested 
fields. However, with each passing year, this source of 
food is becoming less available and we believe that within 
two decades only insignificant amounts of waste grain will 
remain. Thus, ultimately the mallard harvest would be re- 
duced comparably to that of other dabbling ducks. 

Vested interests in waterfowl own at least 4", 535 ha 
(116,960 acres) of the 85,020 ha (210,000 acres) in the 
unleveed portion of the 161,943-ha (400 , 000- acre) Illinois 
River floodplain. Increased diversion would have a devasta- 
ting effect upon this extensive area of the Illinois River 
valley devoted to waterfowl hunting and management. 

Chapter 9. Shorebirds, Gulls, and Terns 

An increased diversion of Lake Michigan water into the 
Illinois River at 6,600 or 10,000 cfs would probably inundate 
all of the mud flats that are now exposed each year by 
natural summer drawdowns. Usage of the Watervv-av bv wading shorehir> 
that rely on the exposed mud flats for feeding and resting 
areas during migration, would probably decrease as mud flats 
became unavailable. The resulting changes in shorebird 
migrational patterns and the overall effects of these changes 
on their populations are difficult to predict. However, 
the loss of mud flats would pose additional hazards to their 
survival. Gulls and terns may be virtually unaffected. 

Chapter 10. Herons and Their Allies 

The effects upon herons and egrets of an increased 
diversion of water into the Illinois Fiver may be both posi- 



21-8 

tive and negative. The primary nest tree species of great ^ 
blue herons, great egrets, black-crowned night herons, and 
green herons are relatively tolerant of flooding. However, 'J 
increased flooding frequency or duration may result in the ], 
death of nesting trees and the subsequent abandonment of the j 
site. Slightly higher water levels nay create more shallow | 
foraging areas for herons and egret? but water levels main- ; 
tained at the tree line of backwater lakes would be excessively 
deep for optimum feeding conditions. Heron populations are 
primarily dependent upon fish populations for food; there- 
fore, factors beneficial to fish, such as increased spawn- 
ing areas, may indirectly aid herons. However, some authori- 
ties believe that the concentration of fish caused by low 
water conditions in the summer is important to foraging 
adult herons as the food requirements of the nestlings ^ 
reach their peak. I 

Overall, an increased diversion is expected to be I 
detrimental to herons and egrets in the Illinois River valley. 
Even minor detrimental effects may further jeopardize the 
precarious conditions of their populations in the project 
area. I 

Chapter 11. Bald Eagles, Doub le -cres ted Cormorants, and I 
Mi 55 i ss ippi Kites I 

Bald Eagles 

Increased diversion mav be partially beneficial and 
detrimental to wintering bald eagles. The most important 
detriment to wintering eagles may be the death of roosting 
trees as a result of flooding. Increased turbidity that may 
result from an enhanced flow of water could affect eagles 
negatively because they depend upon sight to feed. The 
increased flow could be beneficial if it results in more 
open water, areas for feeding. Aspects of increased water 
volume that benefit fish, the eagles' staple food item, 
may indirectly benefit overwintering eagles. Considering 
the endangered statu? of the bald eagle, it is imperative 
that increased diversion is not harmful to the wintering 
populations in Illinois. 

Double- cres ted Cormorants 

Increased diversion would probably have negligible 
effects on cormorants because usage of the project area by 
these birds is currently limited to feeding and resting 
during their fall and spring migration. If higher water 
levels favor fish and other aquatic organisms, then cormor- 
ants may benefit slightly by an increase in food supply. 



21-9 



Mississippi Kite 

Mississippi kites need extensive tracts of bottomland 
timber for nest sites. A possible negative effect on kites 
resulting from increased diversion may be the death of 
nesting trees following prolonged inundation of bottomland 
forest . 

Chapter 12. Other Avifauna 

The effects of an increased diversion on the diverse 
group of avifauna is best analyzed from the habitat and food 
viewpoint. Changing water levels would have the greatest 
impact on the marsh community. Initially, flooding of 
nests would be detrimental to marsh birds. Subsequently, 
a decrease in abundance of marsh habitat may result from 
increased water levels and would probably also have negative 
effects on populations of marsh birds. In the bottomland 
forest habitat, ground- nesting and shrub-nesting avian 
species would be the only birds subject to direct nest 
destruction resulting from high water. Die-offs of hydro- 
phytic willow and buttonbush thickets would probably have 
more permanent detrimental effects on shrub- nesting birds. 
Death of bottomland trees that would result from prolonged 
periods of inundation could be beneficial to cavity- nes t ing 
birds. Highly suitable nesting conditions provided by dead 
trees would probably result in increased woodpecker populations 
Conversely, tree death would probably be detrimental to 
canopy-nesting species that prefer living trees. 

Enhanced water flow could have both positive and negative 
effects on food availability for avifauna. It could pro- 
vide more areas of open water in winter for feeding raptors 
and kingfishers by retarding ice formation. However, if 
increased diversion results in more turbidity, then the cap- 
ture of food by these sight- feeding species may be impaired. 
Cumulative effects of inundation on the seed-, fruit-, and 
nut-bearing plants that small birds depend upon, especiallv 
in winter, are difficult to evaluate but prolonged inundation 
would be detrimental. 



Chapter 15. Mammals 

Increased diversion is expected to be detrimental to 
most terrestrial species, but particularly to the small, 
ground- inhabiting mammals. Increased diversion may ulti- 
mately be beneficial to semi-aquatic mammal species. From 
the economic viewpoint, raccoons and muskrats, the two most 
valuable species of furbearers, would probably be harmed 
and benefited, respectively. Populations of many of the other 
furbearers and small game species would probablv be 



21-10 



adversely affected. White-tailed deer habitat would decline 
if the amount of bottomland forest decreased. 

Chapter 14. State and Federal Areas, Nature Preserves, and 
Natural Areas 

The effects of increased diversion of Lake Michigan 
water into the Illinois River on the natural areas, nature 
preserves, state parks and conservation areas, and federal 
refuges would vary among these areas, and, therefore, are 
difficult to prognosticate. However, these areas are of 
major importance if increased diversion is undertaken because 
of their public usage and concern. These areas may require 
special monitoring of increased diversion to note any 
subsequent effects on plants, animals, and public recreation. 

Chapter 16. Algae (Periphyton and Phy toplankton) 

In the upstream reach of the waterway in Chicago, an 
increased diversion of Lake Michigan water would have the 
following effects: (1) toxic substances, which may limit 
algal growth, would be diluted, and (2) species of algae 
which occur in Lake ^'ichigan, but not in the Illinois 
Waterway, would be washed farther downstream. However, 
the lake species probably would not contribute s igni f i cant 1 v 
to algal populations downstream, because thev would not 
multiply in the turbid, warm waters of the Illinois Water- 
way . 



The increased current velocity caused by increased 
diversion would allow indigenous algae or algae introduced 
from tributaries less time to multiply, thereby reducing 
algal populations in the main channel. If increased diver- 
sion increases turbidity and turbulence in downstream por- 
tions of the waterway, algal populations would decline 
because less light would penetrate for photosynthesis and 
the algae would be repeatedly carried away from the shallow 
photosynthet i c zone at the surface. 

Nutrients, such as nitrogen and phosphorus, are avail- 
able well in excess of the needs of algae in the Illinois 
Waterway, and increased diversion will not dilute them 
enough to limit algal growth. 

Algal growth in the Illinois Waterway and its associated 
lakes and backwaters appears to be limited primarily b%- 
turbidity. Increases in water surface area and volume in the 
channel and in lakes and backwaters due to increased diver- 
sion are unlikely to remove this limitation, since boat 



21-11 



traffic in the main channel and wind-generated waves in the 
backwaters continually resuspend bottom sediments and keep 
the waters turbid all during the growing season. 

Slight decreases in temperature of the upper Illinois 
Waterway due to increased introduction of cooler Lake 
Michigan water probably would not have a measurable impact 
on algae . 



Chapter 1 



Zoopl ank t on 



Increased diversion would increase water velocity and 
both zooplankton and the algae on which they feed would 
have less time to multiply before being washed downstrear^. 
Hence, increased diversion would tend to decrease zooplankton 
populations at least in the upper reaches of tlie Illinois 
Waterway near Chicago. Several genera of rotifers, whic'i 
occur in Lake Michigan and immediately downstream from the 
control structures which admit Lake Michigan water to the 
Illinois Waten%'ay , would probably wash farther downstrear 
with an increase in diversion, but would not multiplv or 
contribute significantly to downstream zooplankton populations. 
If increased diversion increases suspended sediment, species 
of zooplankton which depend on algae for food will decline 
because the algae will have less light for photosynthesis. 
Species of rotifers, cladocerans and copepods which feed 
on organic particles might benefit from an increase in 
suspended particles of organic matter. An increase in 
diversion of relatively cool Lake Michigan water down the 
Illinois Waterv,'ay will lower the temperature of the upper 
waterway slightly, but will have verv little effect on 
zooplankton. Dilution of toxic materials and oxygen- demand- 
ing waste by clean Lake Michigan water would have a bene- 
ficial effect on zooplankton in the upper reaches of the 
Waterway (assuming that they are not all washed doA^-nstrear 
due to increased flows), but pollutants may wash farther 
downs t ream, - thus retarding processes of natural purification 
and prolonging exposure of organisms to the pollutants. In- 
creases in the surface acreage and volume of lakes and 
backwaters in the LaHrange and Peoria Pools due to increased 
diversion, might increase zoopl an]>-ton populations although 
zooplankton would continue to be limited by sedimentation 
and turbidity. If diversion increased the flow of water 
from backwaters to the main channel, zooplankton populations 
in the river would be continuously replenished. In conclusion, 
the effects of increased Lake Michigan diversion on zooplank- 
ton in the Illinois River would be neither wholly beneficial 
nor totally detrimental, but would most likelv alter the specie: 
composition of the zooplankton, with the direction and magni- 
tude of alteration being different in different reaches of 
the waterway. 



21-12 



Chapter 18. Macroi nvertebrates 

If the increased diversion improves water quality and 
oxvgen levels in the upper Illinois River, an increase in 
the numbers and kinds of drift macroinvertebrates which 
colonize solid substrates would be expected. Since Lake 
Michigan could not act as an upstreair. source for drift 
organisms, which are characteristic of streams and rivers, 
the colonization of a cleaner Illinois River would probablv 
proceed from clean downstream tributaries, such as the 
Kankakee River. However, in the bulk of the Illinois River 
and bottomland lakes below the Starved Rock dam, no increase 
in suitable substrates, such as furnished by rooted aouatic 
plants, mussel beds, or firm mud bottoms, is expected to 
result from the increased diversion. 

Lake ^lichigan macroinvertebrates, such as s ideswimmcrs , 
currently inhabit limited portions of the Chicago area 
waterways that receive flow from the Lake. It is likelv 
that these Lake species could extend their range down- 
stream if diversion were increased. 

Benthic macroi nverteb rate communities in the Chicago 
area waterways and in much of the Illinois River downstream 
for a distance of 200 miles appear to be limited by some 
factor or factors associated with polluted sediment. If 
increased diversion increases sediment scour in the Chicago 
area waterways, local conditions might improve for benthic 
macroinvertebrates, at the expense of degrading downstrean 
areas due to the downstream transport of sediment. 

Chapter 19 . Fish 

The beneficial impacts of increased diversion on fish 
populations in the waterway due to improved water quality 
condi tions -wi 1 1 primarily be exerted in the Chicago area 
reaches and the upper Illinois River. Both increased dis- 
solved oxygen concentrations and the dilution of toxicants 
will benefit the fish populations of these reaches. However, 
increased oxygen demands due to ammonia and, occasionally, 
resuspendcd sludge deposits will be extended further down- 
stream and may offset the dissolved oxvgen increases that 
result from using Lake Michigan water for the diversion. 
In addition, the degree to which fish populations in the 
Chicago area reaches of the waterway will be enhanced 
due to water quality improvements will be limited by the 
availability of quality habitats in this reach. 

Fish populations in the middle and lower Illinois River 
will be beneficially impacted bv increases in habitat quantitv 
due to a permanent increase in diversion, but perhaps only 



21-13 



for a few years, until the bottom substrates in the addi- 
tional habitats produced by increased diversion take on the 
same characteristic soft bottoms of the existing bottomland 
habitats and become unsuitable for spawning by nest-building 
species of fish. If diversion is increased and then reduced 
there will be less aquatic habitat available than under 
existing conditions, because the rate of sedimentation will 
increase in slackwatcr areas as the depth increases, and 
less aquatic habitat and more mudflats will be available 
when water levels return to the existing regime. 



c 



SECTION' VI 
REFERENCES 



CHAPTER 22: LITERATURE CITED 

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American Ornithologist's Union. 1957. AOU check-list 
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Anderson, B. G. 1950. The apparent threshholds of 

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Anderson, H. G. 1959. Food habits of migratory ducks 
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Anderson, K. B. 1977. Muse u 1 i urn transversum in the 
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,'R. E. Sparks, and A. A. Paparo. 1978. Rapid 

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Anderson, M. G. 1978. Distribution and production o' 
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22-2 



Arora, H. C. 1966. Rotifera as indicators of trophic 
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Beaufait, W. 1955. Soil profile observations relating 
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22-3 



'ell, D. T. 1974. Tree stratum composition and d i s t r i 
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1945. Relative values of drained and undrained 
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1950. The relationship of muskrat populations 
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22-4 



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22-5 



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22-6 



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22-7 



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22-8 



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22-12 



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